diff --git a/app/graph/types/comment_type.rb b/app/graph/types/comment_type.rb
index 9078257af..36a9f709e 100644
--- a/app/graph/types/comment_type.rb
+++ b/app/graph/types/comment_type.rb
@@ -17,4 +17,5 @@ CommentType = GraphQL::ObjectType.define do
 
   # Linked resources
   field :user, !UserType, "User who made this comment"
+  field :commentable, CommentableInterface, "Element which was commented"
 end
diff --git a/app/graph/types/commentable_interface.rb b/app/graph/types/commentable_interface.rb
new file mode 100644
index 000000000..3bbe96c4f
--- /dev/null
+++ b/app/graph/types/commentable_interface.rb
@@ -0,0 +1,21 @@
+CommentableInterface = GraphQL::InterfaceType.define do
+  name "Commentable"
+
+  field :id, !types.ID, "ID of the commentable"
+  field :title, types.String, "The title of this commentable"
+  field :description, types.String, "The description of this commentable"
+  field :author_id, types.Int, "ID of the author of this commentable"
+  field :comments_count, types.Int, "Number of comments on this commentable"
+
+  # Linked resources
+  field :author, UserType, "Author of this commentable"
+  field :comments, !types[!CommentType], "Comments in this commentable"
+  field :geozone, GeozoneType, "Geozone affected by this commentable"
+end
+
+
+# Then, object types may include it:
+CoffeeType = GraphQL::ObjectType.define do
+  # ...
+  interfaces([BeverageInterface])
+end
diff --git a/app/graph/types/debate_type.rb b/app/graph/types/debate_type.rb
index 095d50688..1cae3a2a4 100644
--- a/app/graph/types/debate_type.rb
+++ b/app/graph/types/debate_type.rb
@@ -1,6 +1,9 @@
 DebateType = GraphQL::ObjectType.define do
   name "Debate"
   description "A single debate entry with associated info"
+
+  interfaces([CommentableInterface])
+
   # Expose fields associated with Debate model
   field :id, !types.ID, "The id of this debate"
   field :title, types.String, "The title of this debate"
diff --git a/app/graph/types/proposal_type.rb b/app/graph/types/proposal_type.rb
index 8456f0a4f..007b5824c 100644
--- a/app/graph/types/proposal_type.rb
+++ b/app/graph/types/proposal_type.rb
@@ -1,6 +1,9 @@
 ProposalType = GraphQL::ObjectType.define do
   name "Proposal"
   description "A single proposal entry returns a proposal with author, total votes and comments"
+
+  interfaces([CommentableInterface])
+  
   # Expose fields associated with Proposal model
   field :id, !types.ID, "The id of this proposal"
   field :title, types.String, "The title of this proposal"