diff --git a/chrono/locale/fr/LC_MESSAGES/django.po b/chrono/locale/fr/LC_MESSAGES/django.po
index aaf57acb..2c89c9b0 100644
--- a/chrono/locale/fr/LC_MESSAGES/django.po
+++ b/chrono/locale/fr/LC_MESSAGES/django.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: chrono 0\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-11-20 19:29+0000\n"
+"POT-Creation-Date: 2019-12-20 12:14+0100\n"
 "PO-Revision-Date: 2018-02-13 17:33+0100\n"
 "Last-Translator: Frederic Peters <fpeters@entrouvert.com>\n"
 "Language: French\n"
@@ -25,13 +25,13 @@ msgstr "Événements"
 msgid "Meetings"
 msgstr "Rendez-vous"
 
-#: agendas/models.py:71 agendas/models.py:252 agendas/models.py:289
-#: agendas/models.py:430
+#: agendas/models.py:71 agendas/models.py:270 agendas/models.py:308
+#: agendas/models.py:470
 msgid "Label"
 msgstr "Libellé"
 
-#: agendas/models.py:72 agendas/models.py:253 agendas/models.py:291
-#: agendas/models.py:431
+#: agendas/models.py:72 agendas/models.py:271 agendas/models.py:314
+#: agendas/models.py:471
 msgid "Identifier"
 msgstr "identifiant"
 
@@ -39,76 +39,72 @@ msgstr "identifiant"
 msgid "Kind"
 msgstr "Type"
 
-#: agendas/models.py:75
+#: agendas/models.py:74
 msgid "Minimal booking delay (in days)"
 msgstr "Délai de réservation minimal (en jours)"
 
-#: agendas/models.py:77
+#: agendas/models.py:76
 msgid "Maximal booking delay (in days)"
 msgstr "Délai de réservation maximal (en jours)"
 
-#: agendas/models.py:79 manager/forms.py:53
+#: agendas/models.py:84 manager/forms.py:60
 msgid "Edit Role"
 msgstr "Rôle d'édition"
 
-#: agendas/models.py:82 manager/forms.py:56
+#: agendas/models.py:93 manager/forms.py:63
 msgid "View Role"
 msgstr "Rôle de visualisation"
 
-#: agendas/models.py:150
+#: agendas/models.py:162
 #, python-format
 msgid "Missing \"%s\" role"
 msgstr "Rôle « %s » manquant"
 
-#: agendas/models.py:191
+#: agendas/models.py:204
 msgid "Week day"
 msgstr "Jour de la semaine"
 
-#: agendas/models.py:192
+#: agendas/models.py:205
 msgid "Start"
 msgstr "Début"
 
-#: agendas/models.py:193
+#: agendas/models.py:206
 msgid "End"
 msgstr "Fin"
 
-#: agendas/models.py:254
+#: agendas/models.py:272
 msgid "Duration (in minutes)"
 msgstr "Durée (en minutes)"
 
-#: agendas/models.py:285
+#: agendas/models.py:304
 msgid "Date/time"
 msgstr "Date et heure"
 
-#: agendas/models.py:286
+#: agendas/models.py:305
 msgid "Places"
 msgstr "Places"
 
-#: agendas/models.py:288
+#: agendas/models.py:306
 msgid "Places in waiting list"
 msgstr "Places dans la liste d'attente"
 
-#: agendas/models.py:290
+#: agendas/models.py:312
 msgid "Optional label to identify this date."
 msgstr "Libellé optionnel pour identifier la date."
 
-#: agendas/models.py:292
+#: agendas/models.py:316
 msgid "Description"
 msgstr "Description"
 
-#: agendas/models.py:293
+#: agendas/models.py:316
 msgid "Optional event description."
 msgstr "Description optionnelle pour l'événement."
 
-#: agendas/models.py:380
+#: agendas/models.py:414
 msgid "Label displayed to user"
 msgstr "Libellé affiché à l'usager"
 
-#: agendas/models.py:433
-msgid "URL to fetch time period exceptions from"
-msgstr "Adresse à laquelle récupérer les exceptions"
-
-#: agendas/models.py:495
+#: agendas/models.py:534
 #, python-format
 msgid ""
 "Failed to retrieve remote calendar (%(url)s, HTTP error %(status_code)s)."
@@ -116,141 +112,141 @@ msgstr ""
 "Erreur à la récupération du calendrier distant (%(url)s, Erreur HTTP "
 "%(status_code)s)."
 
-#: agendas/models.py:499
+#: agendas/models.py:539
 #, python-format
 msgid "Failed to retrieve remote calendar (%(url)s, %(exception)s)."
 msgstr ""
 "Erreur à la récupération du calendrier distant (%(url)s, %(exception)s)."
 
-#: agendas/models.py:511
+#: agendas/models.py:556
 msgid "File format is invalid."
 msgstr "Le format de fichier n'est pas reconnu."
 
-#: agendas/models.py:516
+#: agendas/models.py:561
 msgid "The file doesn't contain any events."
 msgstr "Le fichier ne contient aucun événement."
 
-#: agendas/models.py:524
+#: agendas/models.py:574
 msgid "Exception"
 msgstr "Exception"
 
-#: agendas/models.py:532
+#: agendas/models.py:582
 #, python-format
 msgid "Event \"%s\" has no start date."
 msgstr "L'événement « %s » n'a pas de date de début."
 
-#: agendas/models.py:620
-msgid "External ID"
-msgstr "Identifiant externe"
-
-#: agendas/models.py:621
+#: agendas/models.py:667
 msgid "Optional Label"
 msgstr "Libellé optionnel"
 
-#: agendas/models.py:622
+#: agendas/models.py:668
 msgid "Exception start time"
 msgstr "Début de l'exception"
 
-#: agendas/models.py:623
+#: agendas/models.py:669
 msgid "Exception end time"
 msgstr "Fin de l'exception"
 
-#: agendas/models.py:625
+#: agendas/models.py:671
 msgid "Recurrence ID"
 msgstr "ID de la récurrence"
 
-#: agendas/models.py:659
+#: agendas/models.py:708
 msgid "One or several bookings exists within this time slot."
 msgstr "Des réservatons existent dans cette période."
 
-#: api/views.py:373
+#: api/views.py:430
 msgid "invalid payload"
 msgstr "contenu de requête invalide"
 
-#: api/views.py:384
+#: api/views.py:444
 msgid "slots list cannot be empty"
 msgstr "la liste des créneaux ne peut pas être vide"
 
-#: api/views.py:397
+#: api/views.py:460
 #, python-format
 msgid "invalid value for count (%s)"
 msgstr "valeur invalide pour « count » (%s)"
 
-#: api/views.py:406
+#: api/views.py:472
 msgid "count cannot be less than or equal to zero"
 msgstr "« count » ne peut pas être inférieur ou égal à zéro"
 
-#: api/views.py:418
+#: api/views.py:487
 msgid "cancel_booking_id is not an integer"
 msgstr "« cancel_booking_id » n'est pas un nombre entier"
 
-#: api/views.py:426
+#: api/views.py:497
 msgid "cancel booking: booking already cancelled"
 msgstr "annulation de réservation : réservation déjà annulée"
 
-#: api/views.py:430
+#: api/views.py:504
 msgid "cancel booking: count is different"
 msgstr "annulation de réservation : nombre différent"
 
-#: api/views.py:432
+#: api/views.py:506
 msgid "cancel booking: booking does no exist"
 msgstr "annulation de réservation : réservation inexistante"
 
-#: api/views.py:460
+#: api/views.py:531
 #, python-format
 msgid "invalid slot: %s"
 msgstr "créneau invalide : %s"
 
-#: api/views.py:466
+#: api/views.py:541
 #, python-format
 msgid "all slots must have the same meeting type id (%s)"
 msgstr "tous les créneaux doivent être pour le même type d'événement (%s)"
 
-#: api/views.py:486
+#: api/views.py:565
 msgid "no more desk available"
 msgstr "plus de guichet disponible"
 
-#: api/views.py:520 api/views.py:527
+#: api/views.py:598
+msgid "unknown event identifiers or slugs"
+msgstr "identifiants ou slugs inconnus"
+
+#: api/views.py:612 api/views.py:615
 msgid "sold out"
 msgstr "complet"
 
-#: api/views.py:627
+#: api/views.py:732
 msgid "already cancelled"
 msgstr "déjà annulée"
 
-#: api/views.py:652
+#: api/views.py:759
 msgid "booking is cancelled"
 msgstr "la réservation est annulée"
 
-#: api/views.py:659
+#: api/views.py:766
 msgid "booking is not in waiting list"
 msgstr "la réservation n'est pas dans la liste d'attente"
 
-#: manager/forms.py:106
+#: manager/forms.py:113
 msgid "Days"
 msgstr "Jours"
 
-#: manager/forms.py:109
+#: manager/forms.py:115
 msgid "Start Time"
 msgstr "Heure du début"
 
-#: manager/forms.py:110
+#: manager/forms.py:116
 msgid "End Time"
 msgstr "Heure de fin"
 
-#: manager/forms.py:114 manager/forms.py:130
+#: manager/forms.py:120 manager/forms.py:136
 msgid "End time must come after start time."
 msgstr "L'heure de fin doit venir après l'heure de début."
 
-#: manager/forms.py:164
+#: manager/forms.py:170
 msgid "End datetime must be greater than start datetime."
 msgstr "La date de fin doit venir après la date de début."
 
-#: manager/forms.py:170
+#: manager/forms.py:176
 msgid "Events File"
 msgstr "Fichier d'événements"
 
-#: manager/forms.py:172
+#: manager/forms.py:179
 msgid ""
 "CSV file with date, time, number of places, number of places in waiting "
 "list, and label as columns."
@@ -258,63 +254,67 @@ msgstr ""
 "Fichier CSV avec comme colonnes la date, l'heure, le nombre de places, le "
 "nombre de places sur la liste d'attente et le libellé."
 
-#: manager/forms.py:180
+#: manager/forms.py:193
 msgid "Invalid file format."
 msgstr "Format de fichier invalide."
 
-#: manager/forms.py:208
+#: manager/forms.py:214
 #, python-format
 msgid "Invalid file format. (line %d)"
 msgstr "Format de fichier invalide. (ligne %d)"
 
-#: manager/forms.py:209 manager/templates/chrono/manager_sample_events.txt:1
+#: manager/forms.py:215 manager/templates/chrono/manager_sample_events.txt:1
 msgid "date"
 msgstr "date"
 
-#: manager/forms.py:209
+#: manager/forms.py:215
 msgid "Date"
 msgstr "Date"
 
-#: manager/forms.py:222
+#: manager/forms.py:233
 #, python-format
 msgid "Invalid file format. (date/time format, line %d)"
 msgstr "Format de fichier invalide. (format date/heure, ligne %d)"
 
-#: manager/forms.py:226
+#: manager/forms.py:237
 #, python-format
 msgid "Invalid file format. (number of places, line %d)"
 msgstr "Format de fichier invalide. (nombre de places, ligne %d)"
 
-#: manager/forms.py:231
+#: manager/forms.py:243
 #, python-format
 msgid "Invalid file format. (number of places in waiting list, line %d)"
 msgstr ""
 "Format de fichier invalide. (nombre de places sur la liste d'attente, ligne "
 "%d)"
 
-#: manager/forms.py:243
+#: manager/forms.py:256
 #, python-format
 msgid "Invalid file format. (%(label)s: %(errors)s, line %(line)d)"
 msgstr "Format de fichier invalide. (%(label)s : %(errors)s, ligne %(line)d)"
 
-#: manager/forms.py:258
+#: manager/forms.py:267 manager/forms.py:289
 msgid "ICS File"
 msgstr "Fichier ICS"
 
-#: manager/forms.py:259
+#: manager/forms.py:269 manager/forms.py:291
 msgid "ICS file containing events which will be considered as exceptions."
 msgstr ""
 "Fichier au format ICS dont les événements seront ajoutés comme exceptions."
 
-#: manager/forms.py:260
+#: manager/forms.py:272
 msgid "URL"
 msgstr "URL"
 
-#: manager/forms.py:261
+#: manager/forms.py:274
 msgid "URL to remote calendar which will be synchronised hourly."
 msgstr "Adresse du calendrier distant qui sera synchronisé toutes les heures."
 
-#: manager/forms.py:265
+#: manager/forms.py:284
+msgid "Please provide an ICS File or an URL."
+msgstr "Veuillez fournir un fichier ou l'adresse d'un fichier ICS."
+
+#: manager/forms.py:300
 msgid "Agendas Export File"
 msgstr "Fichier d'agendas"
 
@@ -325,18 +325,21 @@ msgstr "Importation d'agendas"
 #: manager/templates/chrono/agendas_import.html:13
 #: manager/templates/chrono/manager_home.html:8
 #: manager/templates/chrono/manager_import_events.html:27
-#: manager/templates/chrono/manager_import_exceptions.html:22
+#: manager/templates/chrono/manager_import_exceptions.html:54
 msgid "Import"
 msgstr "Importer"
 
 #: manager/templates/chrono/agendas_import.html:14
 #: manager/templates/chrono/manager_agenda_form.html:19
 #: manager/templates/chrono/manager_confirm_delete.html:21
+#: manager/templates/chrono/manager_confirm_exception_delete.html:16
+#: manager/templates/chrono/manager_confirm_source_delete.html:16
 #: manager/templates/chrono/manager_desk_form.html:36
 #: manager/templates/chrono/manager_event_form.html:34
 #: manager/templates/chrono/manager_import_events.html:28
-#: manager/templates/chrono/manager_import_exceptions.html:23
+#: manager/templates/chrono/manager_import_exceptions.html:55
 #: manager/templates/chrono/manager_meeting_type_form.html:34
+#: manager/templates/chrono/manager_replace_exceptions.html:25
 #: manager/templates/chrono/manager_time_period_exception_form.html:36
 #: manager/templates/chrono/manager_time_period_form.html:36
 msgid "Cancel"
@@ -400,13 +403,14 @@ msgid "No opening hours this month."
 msgstr "Pas d'heures d'ouverture ce mois."
 
 #: manager/templates/chrono/manager_agenda_settings.html:15
-#: manager/templates/chrono/manager_agenda_settings.html:53
 #: manager/templates/chrono/manager_agenda_settings.html:99
 msgid "identifier:"
 msgstr "identifiant :"
 
 #: manager/templates/chrono/manager_agenda_settings.html:19
 #: manager/templates/chrono/manager_confirm_delete.html:20
+#: manager/templates/chrono/manager_confirm_exception_delete.html:15
+#: manager/templates/chrono/manager_confirm_source_delete.html:15
 #: manager/templates/chrono/manager_desk_form.html:22
 #: manager/templates/chrono/manager_event_form.html:20
 #: manager/templates/chrono/manager_meeting_type_form.html:20
@@ -473,6 +477,7 @@ msgstr "hors de la période d'inscription"
 #: manager/templates/chrono/manager_agenda_settings.html:129
 #: manager/templates/chrono/manager_agenda_settings.html:135
 #: manager/templates/chrono/manager_agenda_settings.html:148
+#: manager/templates/chrono/manager_import_exceptions.html:40
 #: manager/templates/chrono/manager_time_period_exception_list.html:24
 msgid "remove"
 msgstr "supprimer"
@@ -522,6 +527,7 @@ msgid "Add a time period"
 msgstr "Ajouter une période horaire"
 
 #: manager/templates/chrono/manager_agenda_settings.html:144
+#: manager/templates/chrono/manager_import_exceptions.html:20
 #: manager/templates/chrono/manager_time_period_exception_list.html:15
 msgid "Exceptions"
 msgstr "Exceptions"
@@ -593,7 +599,7 @@ msgstr "Délai de réservation maximal :"
 #: manager/templates/chrono/manager_base.html:13
 #: manager/templates/chrono/manager_base.html:19
 #: manager/templates/chrono/manager_base.html:29
-#: manager/templates/chrono/manager_home.html:5 manager/views.py:825
+#: manager/templates/chrono/manager_home.html:5 manager/views.py:984
 msgid "Agendas"
 msgstr "Agendas"
 
@@ -607,9 +613,17 @@ msgstr ""
 "  "
 
 #: manager/templates/chrono/manager_confirm_delete.html:16
+msgid "Are you sure you want to delete this?"
+msgstr "Êtes-vous sûr de vouloir supprimer ceci ?"
+
+#: manager/templates/chrono/manager_confirm_exception_delete.html:12
 msgid "Are you sure you want to delete this exception?"
 msgstr "Êtes-vous sûr·e de vouloir supprimer cette exception ?"
 
+#: manager/templates/chrono/manager_confirm_source_delete.html:12
+msgid "Are you sure you want to delete this exception source?"
+msgstr "Êtes-vous sûr·e de vouloir supprimer cette source d'exceptions ?"
+
 #: manager/templates/chrono/manager_desk_form.html:20
 msgid "Edit Desk"
 msgstr "Modification du guichet"
@@ -642,16 +656,50 @@ msgstr "Télécharger un fichier d'exemple"
 msgid "Import exceptions"
 msgstr "Importer des exceptions"
 
-#: manager/templates/chrono/manager_import_exceptions.html:16
-msgid "You can upload a file or specify an address to a remote calendar."
+#: manager/templates/chrono/manager_import_exceptions.html:35
+msgid "replace"
+msgstr "remplacer"
+
+#: manager/templates/chrono/manager_import_exceptions.html:37
+msgid "refresh"
+msgstr "rafraîchir"
+
+#: manager/templates/chrono/manager_import_exceptions.html:48
+msgid ""
+"To add new exceptions, you can upload a file or specify an address to a "
+"remote calendar."
 msgstr ""
-"Vous pouvez télécharger un fichier ou spécifier l'adresse d'un calendrier "
-"distant."
+"Pour ajouter de nouvelles exceptions, vous pouvez transférer un fichier ou indiquer "
+"l'adresse d'un calendrier distant."
 
 #: manager/templates/chrono/manager_meeting_type_form.html:18
 msgid "Edit Meeting Type"
 msgstr "Modification du type de rendez-vous"
 
+#: manager/templates/chrono/manager_replace_exceptions.html:5
+msgid "Replace exceptions"
+msgstr "Remplacer les exceptions"
+
+#: manager/templates/chrono/manager_replace_exceptions.html:5
+msgid "Refresh exceptions"
+msgstr "Rafraîchir les exceptions"
+
+#: manager/templates/chrono/manager_replace_exceptions.html:11
+msgid "To replace existing exceptions, please upload a new file."
+msgstr "Pour remplacer les exceptions, veuillez transférer un fichier."
+
+#: manager/templates/chrono/manager_replace_exceptions.html:14
+msgid "Press the button \"Refresh\" to refresh existing exceptions from:"
+msgstr "Cliquer sur le boutton \"Rafraîchir\" pour rafraîchir les exceptions existantes depuis :"
+
+#: manager/templates/chrono/manager_replace_exceptions.html:24
+msgid "Replace"
+msgstr "Remplacer"
+
+#: manager/templates/chrono/manager_replace_exceptions.html:24
+msgid "Refresh"
+msgstr "Rafraîchir"
+
 #: manager/templates/chrono/manager_sample_events.txt:1
 msgid "time"
 msgstr "heure"
@@ -706,52 +754,62 @@ msgstr "Modification de la période horaire"
 msgid "Log in"
 msgstr "Se connecter"
 
-#: manager/views.py:72
+#: manager/views.py:105
 msgid "Desk 1"
 msgstr "Guichet 1"
 
-#: manager/views.py:96
+#: manager/views.py:130
 msgid "File is not in the expected JSON format."
 msgstr "Le fichier n'est pas dans le format JSON attendu."
 
-#: manager/views.py:106
+#: manager/views.py:140
 msgid "No agendas were found."
 msgstr "Aucun agenda trouvé."
 
-#: manager/views.py:109
+#: manager/views.py:143
 msgid "No agenda created."
 msgstr "Aucun agenda créé."
 
-#: manager/views.py:111
+#: manager/views.py:146
 #, python-format
 msgid "An agenda has been created."
 msgid_plural "%(count)d agendas have been created."
 msgstr[0] "Un agenda a été créé."
 msgstr[1] "%(count)d agendas on t été créés."
 
-#: manager/views.py:116
+#: manager/views.py:150
 msgid "No agenda updated."
 msgstr "Aucun agenda mis à jour."
 
-#: manager/views.py:118
+#: manager/views.py:153
 #, python-format
 msgid "An agenda has been updated."
 msgid_plural "%(count)d agendas have been updated."
 msgstr[0] "Un agenda a été mis à jour."
 msgstr[1] "%(count)d agendas ont été mis à jour."
 
-#: manager/views.py:599
+#: manager/views.py:677
+msgid "Duplicated event identifier"
+msgstr "Doublon d'identifiant d'évènement"
+
+#: manager/views.py:679
 #, python-format
 msgid "%d events have been imported."
 msgstr "%d événements ont été importés."
 
-#: manager/views.py:815
+#: manager/views.py:909 manager/views.py:947 manager/views.py:970
 #, python-format
 msgid "An exception has been imported."
 msgid_plural "%(count)d exceptions have been imported."
 msgstr[0] "Une exception a été importée."
 msgstr[1] "%(count)d exceptions ont été importées."
 
+#~ msgid "URL to fetch time period exceptions from"
+#~ msgstr "Adresse à laquelle récupérer les exceptions"
+
+#~ msgid "External ID"
+#~ msgstr "Identifiant externe"
+
 #~ msgid "Slug"
 #~ msgstr "Slug"