diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index 6561b8d..0b46dd9 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -96,6 +96,14 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
          %User{} = user <- User.get_or_fetch_by_ap_id(data["actor"]) do
       object = fix_object(data["object"])
 
+      # mark incoming messages from switter with media as nsfw
+      if String.contains?(data["actor"], "switter.at") and object["attachment"] != nil and length(object["attachment"]) > 0 do
+        tags = (object["tag"] || []) ++ ["nsfw"]
+        object = Map.put(object, "tags", tags)
+        object = Map.put(object, "sensitive", true)
+        Logger.info("added #nsfw tag to #{data["id"]}")
+      end
+
       params = %{
         to: data["to"],
         object: object,