diff --git a/src/models.py b/src/models.py
index 0d9e389..93445e2 100644
--- a/src/models.py
+++ b/src/models.py
@@ -96,7 +96,7 @@ class SourceCreate(BaseModel):
     url: Optional[str] = None
     domain: Optional[str] = None
     source_type: str = Field(default="rss_feed", pattern="^(rss_feed|web_source|excluded)$")
-    category: str = Field(default="sonstige", pattern="^(nachrichtenagentur|oeffentlich-rechtlich|qualitaetszeitung|behoerde|fachmedien|think-tank|international|regional|sonstige)$")
+    category: str = Field(default="sonstige", pattern="^(nachrichtenagentur|oeffentlich-rechtlich|qualitaetszeitung|behoerde|fachmedien|think-tank|international|regional|boulevard|sonstige)$")
     status: str = Field(default="active", pattern="^(active|inactive)$")
     notes: Optional[str] = None
 
@@ -106,7 +106,7 @@ class SourceUpdate(BaseModel):
     url: Optional[str] = None
     domain: Optional[str] = None
     source_type: Optional[str] = Field(default=None, pattern="^(rss_feed|web_source|excluded)$")
-    category: Optional[str] = Field(default=None, pattern="^(nachrichtenagentur|oeffentlich-rechtlich|qualitaetszeitung|behoerde|fachmedien|think-tank|international|regional|sonstige)$")
+    category: Optional[str] = Field(default=None, pattern="^(nachrichtenagentur|oeffentlich-rechtlich|qualitaetszeitung|behoerde|fachmedien|think-tank|international|regional|boulevard|sonstige)$")
     status: Optional[str] = Field(default=None, pattern="^(active|inactive)$")
     notes: Optional[str] = None
 
diff --git a/src/routers/sources.py b/src/routers/sources.py
index fb1b2f3..1cebb8e 100644
--- a/src/routers/sources.py
+++ b/src/routers/sources.py
@@ -5,7 +5,7 @@ from fastapi import APIRouter, Depends, HTTPException, status
 from models import SourceCreate, SourceUpdate, SourceResponse, DiscoverRequest, DiscoverResponse, DiscoverMultiResponse, DomainActionRequest
 from auth import get_current_user
 from database import db_dependency, refresh_source_counts
-from source_rules import discover_source, discover_all_feeds, evaluate_feeds_with_claude, _extract_domain, _detect_category, domain_to_display_name
+from source_rules import discover_source, discover_all_feeds, evaluate_feeds_with_claude, _extract_domain, _detect_category, domain_to_display_name, _DOMAIN_ALIASES
 import aiosqlite
 
 logger = logging.getLogger("osint.sources")
@@ -16,14 +16,13 @@ SOURCE_UPDATE_COLUMNS = {"name", "url", "domain", "source_type", "category", "st
 
 
 def _check_source_ownership(source: dict, username: str):
-    """Prueft ob der Nutzer die Quelle bearbeiten/loeschen darf."""
+    """Prueft ob der Nutzer die Quelle bearbeiten/loeschen darf.
+
+    System-Quellen (auto-entdeckt) duerfen von jedem bearbeitet werden.
+    Nutzer-Quellen nur vom Ersteller.
+    """
     added_by = source.get("added_by", "")
-    if added_by == "system":
-        raise HTTPException(
-            status_code=status.HTTP_403_FORBIDDEN,
-            detail="System-Quellen koennen nicht veraendert werden",
-        )
-    if added_by and added_by != username:
+    if added_by and added_by != "system" and added_by != username:
         raise HTTPException(
             status_code=status.HTTP_403_FORBIDDEN,
             detail="Nur der Ersteller kann diese Quelle bearbeiten",
@@ -442,13 +441,32 @@ async def create_source(
 ):
     """Neue Quelle hinzufuegen (org-spezifisch)."""
     tenant_id = current_user.get("tenant_id")
+
+    # Domain normalisieren (Subdomain-Aliase auflösen)
+    domain = data.domain
+    if domain:
+        domain = _DOMAIN_ALIASES.get(domain.lower(), domain.lower())
+
+    # Duplikat-Prüfung: gleiche URL bereits vorhanden?
+    if data.url:
+        cursor = await db.execute(
+            "SELECT id, name FROM sources WHERE url = ? AND status = 'active'",
+            (data.url,),
+        )
+        existing = await cursor.fetchone()
+        if existing:
+            raise HTTPException(
+                status_code=status.HTTP_409_CONFLICT,
+                detail=f"Feed-URL bereits vorhanden: {existing['name']} (ID {existing['id']})",
+            )
+
     cursor = await db.execute(
         """INSERT INTO sources (name, url, domain, source_type, category, status, notes, added_by, tenant_id)
            VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)""",
         (
             data.name,
             data.url,
-            data.domain,
+            domain,
             data.source_type,
             data.category,
             data.status,
@@ -483,6 +501,9 @@ async def update_source(
     for field, value in data.model_dump(exclude_none=True).items():
         if field not in SOURCE_UPDATE_COLUMNS:
             continue
+        # Domain normalisieren
+        if field == "domain" and value:
+            value = _DOMAIN_ALIASES.get(value.lower(), value.lower())
         updates[field] = value
 
     if not updates:
diff --git a/src/static/dashboard.html b/src/static/dashboard.html
index c0169c2..cfe82d7 100644
--- a/src/static/dashboard.html
+++ b/src/static/dashboard.html
@@ -420,6 +420,7 @@
                             <option value="think-tank">Think Tank</option>
                             <option value="international">International</option>
                             <option value="regional">Regional</option>
+                            <option value="boulevard">Boulevard</option>
                             <option value="sonstige">Sonstige</option>
                         </select>
                         <label for="sources-search" class="sr-only">Quellen durchsuchen</label>
@@ -475,6 +476,7 @@
                                     <option value="think-tank">Think Tank</option>
                                     <option value="international">International</option>
                                     <option value="regional">Regional</option>
+                                    <option value="boulevard">Boulevard</option>
                                     <option value="sonstige" selected>Sonstige</option>
                                 </select>
                             </div>
diff --git a/src/static/js/components.js b/src/static/js/components.js
index cbd35fa..a24d132 100644
--- a/src/static/js/components.js
+++ b/src/static/js/components.js
@@ -506,6 +506,7 @@ const UI = {
         'think-tank': 'Think Tank',
         'international': 'Intl.',
         'regional': 'Regional',
+        'boulevard': 'Boulevard',
         'sonstige': 'Sonstige',
     },