diff --git a/frontools/config.py b/frontools/config.py
index 5e59973..c4fa0c6 100644
--- a/frontools/config.py
+++ b/frontools/config.py
@@ -87,6 +87,10 @@ class Config:
             if self._filter(url, tags):
                 yield theme, url
 
+    def add_local_themes_root(self, *directories: Union[Path, str]) -> None:
+        """Add an url for a theme"""
+        self._theme_index.add_local_themes_root(*[Path(it) for it in directories])
+
     def add_urls(self, *urls: UrlEntry) -> None:
         """Add an url for a theme"""
         self._theme_index.add_urls(*urls)
diff --git a/frontools/theme_index.py b/frontools/theme_index.py
index 5df26b8..4983578 100644
--- a/frontools/theme_index.py
+++ b/frontools/theme_index.py
@@ -35,6 +35,7 @@ class ThemeIndex:
     def __init__(self) -> None:
         self._themes: ThemeIndexData = {}
         self._inputs = _Inputs()
+        self._local_theme_roots: list[Path] = []
 
     @property
     def urls(self) -> Iterable[tuple[str, str, set[str]]]:
@@ -43,6 +44,10 @@ class ThemeIndex:
             for url, tags in theme.items():
                 yield theme_name, url, set(tags)
 
+    def add_local_themes_root(self, *directories: Path) -> None:
+        """Add an url for a theme"""
+        self._local_theme_roots.extend(directories)
+
     def add_urls(self, *urls: UrlEntry) -> None:
         """Add an url for a theme"""
         self._inputs.urls.extend(urls)
@@ -66,6 +71,31 @@ class ThemeIndex:
                 dump(self._themes, index_cache_handle)
 
         self._load_yaml_files()
+        self._check_local_themes()
+
+    def _check_local_themes(self) -> None:
+        local_themes: set[str] = set()
+        for theme_root in self._local_theme_roots:
+            local_themes.update(set(_get_local_themes(theme_root)))
+
+        config_themes = set(self._themes)
+
+        unknown_themes = config_themes - local_themes
+        unconfigured_themes = local_themes - config_themes
+
+        if unknown_themes:
+            _LOGGER.warn(
+                "* Following themes are present in index but have no local source :"
+            )
+            for theme_name in sorted(unknown_themes):
+                _LOGGER.warn(theme_name)
+
+        if unconfigured_themes:
+            _LOGGER.warn(
+                "* Following themes are present in local sources but have no url configured in index :"
+            )
+            for theme_name in sorted(unconfigured_themes):
+                _LOGGER.warn(theme_name)
 
     async def _load_urls_without_theme(self) -> None:
         async def _load(url: str, tags: list[str]) -> None:
@@ -221,3 +251,14 @@ async def _get_node_urls(
                 if service_id == "authentic":
                     base_url = base_url + "login/"
                 yield (base_url, [service_id], theme)
+
+
+def _get_local_themes(root: Path) -> Iterable[str]:
+    static = root / "static"
+    for theme_dir in static.iterdir():
+        theme_scss = theme_dir / "style.scss"
+
+        if not theme_scss.is_file():
+            continue
+
+        yield theme_dir.name