diff --git a/pretalx_pages/models.py b/pretalx_pages/models.py
index 706ddbc..34032b3 100644
--- a/pretalx_pages/models.py
+++ b/pretalx_pages/models.py
@@ -15,7 +15,7 @@ class Page(LogMixin, models.Model):
         verbose_name=_("URL to static page"),
         validators=[
             RegexValidator(
-                regex="^[a-zA-Z0-9.-]+$",
+                regex="^[a-zA-Z0-9][a-zA-Z0-9.-]+$",
                 message=_(
                     "The slug may only contain letters, numbers, dots and dashes."
                 ),
diff --git a/pretalx_pages/urls.py b/pretalx_pages/urls.py
index a4aa4c4..5031c38 100644
--- a/pretalx_pages/urls.py
+++ b/pretalx_pages/urls.py
@@ -1,41 +1,41 @@
 from django.urls import re_path
-from pretalx.event.models.event import SLUG_CHARS
+from pretalx.event.models.event import SLUG_REGEX
 
 from . import views
 
 urlpatterns = [
     re_path(
-        rf"^orga/event/(?P<event>[{SLUG_CHARS}]+)/pages/$",
+        rf"^orga/event/(?P<event>{SLUG_REGEX})/pages/$",
         views.PageList.as_view(),
         name="index",
     ),
     re_path(
-        rf"^orga/event/(?P<event>[{SLUG_CHARS}]+)/pages/create$",
+        rf"^orga/event/(?P<event>{SLUG_REGEX})/pages/create$",
         views.PageCreate.as_view(),
         name="create",
     ),
     re_path(
-        rf"^orga/event/(?P<event>[{SLUG_CHARS}]+)/pages/(?P<page>[{SLUG_CHARS}]+)/$",
+        rf"^orga/event/(?P<event>{SLUG_REGEX})/pages/(?P<page>{SLUG_REGEX})/$",
         views.PageUpdate.as_view(),
         name="edit",
     ),
     re_path(
-        rf"^orga/event/(?P<event>[{SLUG_CHARS}]+)/pages/(?P<page>[{SLUG_CHARS}]+)/delete$",
+        rf"^orga/event/(?P<event>{SLUG_REGEX})/pages/(?P<page>{SLUG_REGEX})/delete$",
         views.PageDelete.as_view(),
         name="delete",
     ),
     re_path(
-        rf"^orga/event/(?P<event>[{SLUG_CHARS}]+)/pages/(?P<page>[{SLUG_CHARS}]+)/up$",
+        rf"^orga/event/(?P<event>{SLUG_REGEX})/pages/(?P<page>{SLUG_REGEX})/up$",
         views.page_move_up,
         name="up",
     ),
     re_path(
-        rf"^orga/event/(?P<event>[{SLUG_CHARS}]+)/pages/(?P<page>[{SLUG_CHARS}]+)/down$",
+        rf"^orga/event/(?P<event>{SLUG_REGEX})/pages/(?P<page>{SLUG_REGEX})/down$",
         views.page_move_down,
         name="down",
     ),
     re_path(
-        rf"^(?P<event>[{SLUG_CHARS}]+)/page/(?P<slug>[^/]+)/$",
+        rf"^(?P<event>{SLUG_REGEX})/page/(?P<slug>[^/]+)/$",
         views.ShowPageView.as_view(),
         name="show",
     ),