diff --git a/diracx-routers/src/diracx/routers/auth/authorize_code_flow.py b/diracx-routers/src/diracx/routers/auth/authorize_code_flow.py
index b8dd156c8..733e922c9 100644
--- a/diracx-routers/src/diracx/routers/auth/authorize_code_flow.py
+++ b/diracx-routers/src/diracx/routers/auth/authorize_code_flow.py
@@ -90,6 +90,11 @@ async def authorization_flow(
             status_code=status.HTTP_400_BAD_REQUEST,
             detail=e.args[0],
         ) from e
+    except PermissionError as e:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail=e.args[0],
+        ) from e
 
     uuid = await auth_db.insert_authorization_flow(
         client_id,
diff --git a/diracx-routers/src/diracx/routers/auth/device_flow.py b/diracx-routers/src/diracx/routers/auth/device_flow.py
index d311715b7..246275175 100644
--- a/diracx-routers/src/diracx/routers/auth/device_flow.py
+++ b/diracx-routers/src/diracx/routers/auth/device_flow.py
@@ -120,6 +120,11 @@ async def initiate_device_flow(
             status_code=status.HTTP_400_BAD_REQUEST,
             detail=e.args[0],
         ) from e
+    except PermissionError as e:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail=e.args[0],
+        ) from e
 
     user_code, device_code = await auth_db.insert_device_flow(
         client_id, scope, audience
diff --git a/diracx-routers/src/diracx/routers/auth/token.py b/diracx-routers/src/diracx/routers/auth/token.py
index ce4161f0e..17c3e94fa 100644
--- a/diracx-routers/src/diracx/routers/auth/token.py
+++ b/diracx-routers/src/diracx/routers/auth/token.py
@@ -313,6 +313,11 @@ async def legacy_exchange(
             status_code=status.HTTP_400_BAD_REQUEST,
             detail="Invalid scope or preferred_username",
         ) from e
+    except PermissionError as e:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail=e.args[0],
+        ) from e
 
     return await exchange_token(
         auth_db,
diff --git a/diracx-routers/src/diracx/routers/auth/utils.py b/diracx-routers/src/diracx/routers/auth/utils.py
index a23ac9b82..914d491c0 100644
--- a/diracx-routers/src/diracx/routers/auth/utils.py
+++ b/diracx-routers/src/diracx/routers/auth/utils.py
@@ -297,15 +297,22 @@ def parse_and_validate_scope(
         if group not in config.Registry[vo].Groups:
             raise ValueError(f"{group} not in {vo} groups")
 
+    allowed_properties = config.Registry[vo].Groups[group].Properties
     if not properties:
         # If there are no properties set get the defaults from the CS
-        properties = [str(p) for p in config.Registry[vo].Groups[group].Properties]
+        properties = [str(p) for p in allowed_properties]
 
     if not set(properties).issubset(available_properties):
         raise ValueError(
             f"{set(properties)-set(available_properties)} are not valid properties"
         )
 
+    if not set(properties).issubset(allowed_properties):
+        raise PermissionError(
+            f"Attempted to access properties {set(properties)-set(allowed_properties)} which are not allowed."
+            f" Allowed properties are: {allowed_properties}"
+        )
+
     return {
         "group": group,
         "properties": sorted(properties),
diff --git a/diracx-routers/tests/auth/test_standard.py b/diracx-routers/tests/auth/test_standard.py
index aa72de17c..f48862135 100644
--- a/diracx-routers/tests/auth/test_standard.py
+++ b/diracx-routers/tests/auth/test_standard.py
@@ -184,7 +184,7 @@ async def test_device_flow(test_client, auth_httpx_mock: HTTPXMock):
         params={
             "client_id": DIRAC_CLIENT_ID,
             "audience": "Dirac server",
-            "scope": "vo:lhcb group:lhcb_user property:FileCatalogManagement property:NormalUser",
+            "scope": "vo:lhcb group:lhcb_user property:NormalUser",
         },
     )
     assert r.status_code == 200, r.json()
@@ -253,6 +253,92 @@ async def test_device_flow(test_client, auth_httpx_mock: HTTPXMock):
     assert r.json()["detail"] == "Code was already used"
 
 
+async def test_flows_with_unallowed_properties(test_client):
+    """Test the authorization flow and the device flow with unallowed properties."""
+    unallowed_property = "FileCatalogManagement"
+
+    # Initiate the authorization flow
+    code_verifier = secrets.token_hex()
+    code_challenge = (
+        base64.urlsafe_b64encode(hashlib.sha256(code_verifier.encode()).digest())
+        .decode()
+        .replace("=", "")
+    )
+    r = test_client.get(
+        "/api/auth/authorize",
+        params={
+            "response_type": "code",
+            "code_challenge": code_challenge,
+            "code_challenge_method": "S256",
+            "client_id": DIRAC_CLIENT_ID,
+            "redirect_uri": "http://diracx.test.invalid:8000/api/docs/oauth2-redirect",
+            "scope": f"vo:lhcb property:{unallowed_property} property:NormalUser",
+            "state": "external-state",
+        },
+        follow_redirects=False,
+    )
+    assert r.status_code == 403, r.json()
+    assert (
+        f"Attempted to access properties {{'{unallowed_property}'}} which are not allowed."
+        in r.json()["detail"]
+    )
+
+    # Initiate the device flow
+    r = test_client.post(
+        "/api/auth/device",
+        params={
+            "client_id": DIRAC_CLIENT_ID,
+            "audience": "Dirac server",
+            "scope": f"vo:lhcb group:lhcb_user property:{unallowed_property} property:NormalUser",
+        },
+    )
+    assert r.status_code == 403, r.json()
+    assert (
+        f"Attempted to access properties {{'{unallowed_property}'}} which are not allowed."
+        in r.json()["detail"]
+    )
+
+
+async def test_flows_with_invalid_properties(test_client):
+    """Test the authorization flow and the device flow with invalid properties."""
+    invalid_property = "InvalidAndUnknownProperty"
+
+    # Initiate the authorization flow
+    code_verifier = secrets.token_hex()
+    code_challenge = (
+        base64.urlsafe_b64encode(hashlib.sha256(code_verifier.encode()).digest())
+        .decode()
+        .replace("=", "")
+    )
+    r = test_client.get(
+        "/api/auth/authorize",
+        params={
+            "response_type": "code",
+            "code_challenge": code_challenge,
+            "code_challenge_method": "S256",
+            "client_id": DIRAC_CLIENT_ID,
+            "redirect_uri": "http://diracx.test.invalid:8000/api/docs/oauth2-redirect",
+            "scope": f"vo:lhcb property:{invalid_property} property:NormalUser",
+            "state": "external-state",
+        },
+        follow_redirects=False,
+    )
+    assert r.status_code == 400, r.json()
+    assert f"{{'{invalid_property}'}} are not valid properties" in r.json()["detail"]
+
+    # Initiate the device flow
+    r = test_client.post(
+        "/api/auth/device",
+        params={
+            "client_id": DIRAC_CLIENT_ID,
+            "audience": "Dirac server",
+            "scope": f"vo:lhcb group:lhcb_user property:{invalid_property} property:NormalUser",
+        },
+    )
+    assert r.status_code == 400, r.json()
+    assert f"{{'{invalid_property}'}} are not valid properties" in r.json()["detail"]
+
+
 async def test_refresh_token_rotation(test_client, auth_httpx_mock: HTTPXMock):
     """Test the refresh token rotation.
     - initiate a device code flow to get an initial refresh token
@@ -576,7 +662,7 @@ def _get_tokens(
         params={
             "client_id": DIRAC_CLIENT_ID,
             "audience": "Dirac server",
-            "scope": f"vo:lhcb group:{group} property:FileCatalogManagement property:{property}",
+            "scope": f"vo:lhcb group:{group} property:{property}",
         },
     )
     data = r.json()