diff --git a/net/server/internal/api_content.go b/net/server/internal/api_content.go
index 857a7a40..8b3c1c8f 100644
--- a/net/server/internal/api_content.go
+++ b/net/server/internal/api_content.go
@@ -23,8 +23,4 @@ func RemoveChannelTopic(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 }
 
-func RemoveChannelTopicTag(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-	w.WriteHeader(http.StatusOK)
-}
 
diff --git a/net/server/internal/api_removeChannelTopicTag.go b/net/server/internal/api_removeChannelTopicTag.go
new file mode 100644
index 00000000..df3b5096
--- /dev/null
+++ b/net/server/internal/api_removeChannelTopicTag.go
@@ -0,0 +1,120 @@
+package databag
+
+import (
+  "time"
+  "errors"
+  "net/http"
+  "gorm.io/gorm"
+  "github.com/gorilla/mux"
+  "databag/internal/store"
+)
+
+func RemoveChannelTopicTag(w http.ResponseWriter, r *http.Request) {
+
+  // scan parameters
+  params := mux.Vars(r)
+  channelId := params["channelId"]
+  topicId := params["topicId"]
+  tagId := params["tagId"]
+
+  channelSlot, guid, err, code := getChannelSlot(r, false)
+  if err != nil {
+    ErrResponse(w, code, err)
+    return
+  }
+  act := &channelSlot.Account
+
+  // load topic
+  var topicSlot store.TopicSlot
+  if ret := store.DB.Preload("Topic.Tags.TagSlot").Preload("Topic.Channel.ChannelSlot").Where("account_id = ? AND topic_slot_id = ?", act.ID, topicId).First(&topicSlot).Error; ret != nil {
+    if errors.Is(err, gorm.ErrRecordNotFound) {
+      ErrResponse(w, http.StatusNotFound, ret)
+    } else {
+      ErrResponse(w, http.StatusInternalServerError, ret)
+    }
+  }
+  if topicSlot.Topic == nil {
+    ErrResponse(w, http.StatusNotFound, errors.New("referenced empty topic"))
+    return
+  }
+  if topicSlot.Topic.Channel.ChannelSlot.ChannelSlotId != channelId {
+    ErrResponse(w, http.StatusNotFound, errors.New("channel topic not found"))
+    return
+  }
+
+  // extract specified tag
+  var tag *store.Tag
+  var tags []store.Tag
+  for _, t := range topicSlot.Topic.Tags {
+    if t.TagSlot.TagSlotId == tagId {
+      tag = &t
+    } else {
+      tags = append(tags, t)
+    }
+  }
+  topicSlot.Topic.Tags = tags;
+
+  // check if tag was found
+  if tag == nil {
+    ErrResponse(w, http.StatusNotFound, errors.New("tag not found"))
+    return
+  }
+
+  // check permission
+  if tag.Guid != guid {
+    ErrResponse(w, http.StatusUnauthorized, errors.New("not creator of tag"))
+    return
+  }
+
+  err = store.DB.Transaction(func(tx *gorm.DB) error {
+
+    if res := tx.Delete(tag).Error; res != nil {
+      return res
+    }
+    if res := tx.Model(&tag.TagSlot).Update("revision", act.ChannelRevision + 1).Error; res != nil {
+      return res
+    }
+    if res := tx.Model(&topicSlot.Topic).Update("tag_count", len(topicSlot.Topic.Tags)).Error; res != nil {
+      return res
+    }
+    if res := tx.Model(&topicSlot.Topic).Update("tag_revision", act.ChannelRevision + 1).Error; res != nil {
+      return res
+    }
+    if res := tx.Model(&topicSlot.Topic).Update("tag_updated", time.Now().Unix()).Error; res != nil {
+      return res
+    }
+    if res := tx.Model(&topicSlot).Update("revision", act.ChannelRevision + 1).Error; res != nil {
+      return res
+    }
+    if res := tx.Model(&channelSlot).Update("revision", act.ChannelRevision + 1).Error; res != nil {
+      return res
+    }
+    if res := tx.Model(act).Update("channel_revision", act.ChannelRevision + 1).Error; res != nil {
+      return res
+    }
+    return nil
+  })
+  if err != nil {
+    ErrResponse(w, http.StatusInternalServerError, err)
+    return
+  }
+
+  // determine affected contact list
+  cards := make(map[string]store.Card)
+  for _, card := range channelSlot.Channel.Cards {
+    cards[card.Guid] = card
+  }
+  for _, group := range channelSlot.Channel.Groups {
+    for _, card := range group.Cards {
+      cards[card.Guid] = card
+    }
+  }
+
+  SetStatus(act)
+  for _, card := range cards {
+    SetContactChannelNotification(act, &card)
+  }
+  WriteResponse(w, nil)
+}
+
+
diff --git a/net/server/internal/ucTopicShare_test.go b/net/server/internal/ucTopicShare_test.go
index 7017c7e1..5d2c876a 100644
--- a/net/server/internal/ucTopicShare_test.go
+++ b/net/server/internal/ucTopicShare_test.go
@@ -17,6 +17,8 @@ func TestTopicShare(t *testing.T) {
   header := make(map[string][]string)
   var err error
   var data []byte
+  var aRev *Revision
+  var cRev *Revision
 
   // setup testing group
   set, err := AddTestGroup("topicshare")
@@ -101,17 +103,35 @@ func TestTopicShare(t *testing.T) {
   assert.NoError(t, ApiTestMsg(GetChannelTopics, "GET", "/content/channels/{channelId}/topics",
     &params, nil, APP_TOKENAPP, set.A.Token, topics, nil))
 
+  aRev = GetTestRevision(set.A.Revisions)
+  cRev = GetTestRevision(set.C.Revisions)
+
   // add a tag to topic
   tag := Tag{}
   subject = &Subject{ DataType: "tagdatatype", Data: "subjectfromA" }
   assert.NoError(t, ApiTestMsg(AddChannelTopicTag, "POST", "/content/channels/{channelId}/topics/{topicId}",
-    &params, subject, APP_TOKENAPP, set.A.Token, tag, nil))
+    &params, subject, APP_TOKENAPP, set.A.Token, &tag, nil))
+
+  assert.NotEqual(t, aRev.Channel, GetTestRevision(set.A.Revisions).Channel)
+  assert.NotEqual(t, cRev.Card, GetTestRevision(set.C.Revisions).Card)
 
   // get tags for topic
-  tags := []Tag{}
+  tags := &[]Tag{}
   assert.NoError(t, ApiTestMsg(GetChannelTopicTags, "GET", "/content/channels/{channelId}/topics/{topicId}",
-    &params, nil, APP_TOKENCONTACT, set.C.A.Token, &tags, nil))
-  assert.Equal(t, 1, len(tags))
+    &params, nil, APP_TOKENCONTACT, set.C.A.Token, tags, nil))
+  assert.Equal(t, 1, len(*tags))
+
+  // delete topic tag
+  params["tagId"] = tag.Id
+  assert.NoError(t, ApiTestMsg(RemoveChannelTopicTag, "DELETE", "/content/channels/{channelId}/topics/{topicId}/tags/{tagId}",
+    &params, nil, APP_TOKENAPP, set.A.Token, nil, nil))
+
+  // get tags for topic
+  tags = &[]Tag{}
+  assert.NoError(t, ApiTestMsg(GetChannelTopicTags, "GET", "/content/channels/{channelId}/topics/{topicId}",
+    &params, nil, APP_TOKENCONTACT, set.C.A.Token, tags, nil))
+PrintMsg(tags)
+  assert.Equal(t, 0, len(*tags))
 
   // get list of assets
   assets = []Asset{}