diff --git a/fet2020/intern/models.py b/fet2020/intern/models.py
index 42c4b2a3..3e77131f 100644
--- a/fet2020/intern/models.py
+++ b/fet2020/intern/models.py
@@ -40,12 +40,10 @@ class TopicGroup(models.Model):
     def get_absolute_url(self):
         return reverse("intern:index") + "#" + self.slug
 
-    def save(self, *args, **kwargs):
+    def clean(self, *args, **kwargs):
         if not self.slug:
             self.slug = slugify(self.shortterm)
 
-        super().save(*args, **kwargs)
-
 
 class Topic(models.Model):
     title = models.CharField(verbose_name="Titel", max_length=128)
@@ -76,11 +74,9 @@ class Topic(models.Model):
     def get_absolute_url(self):
         return reverse("intern:topic", kwargs={"slug": self.slug})
 
-    def save(self, *args, **kwargs):
+    def clean(self, *args, **kwargs):
         if not self.slug:
-            self.slug = slugify(self.title)
-
-        super().save(*args, **kwargs)
+            self.slug = slugify(self.shortterm)
 
 
 class Attachment(models.Model):
@@ -117,12 +113,10 @@ class Attachment(models.Model):
 
         return reverse("intern:attachment", kwargs=kwargs)
 
-    def save(self, *args, **kwargs):
+    def clean(self, *args, **kwargs):
         if not self.slug:
             self.slug = slugify(self.shortterm)
 
-        super().save(*args, **kwargs)
-
 
 class Etherpad(models.Model):
     title = models.CharField(verbose_name="Titel", max_length=128)