diff --git a/aider/repomap.py b/aider/repomap.py
index 9f8eced7b..eb43acc49 100644
--- a/aider/repomap.py
+++ b/aider/repomap.py
@@ -32,7 +32,10 @@ def to_tree(tags):
     # add a bogus tag at the end so we trip the this_fname != cur_fname...
     dummy_tag = (None,)
     for tag in tags + [dummy_tag]:
-        this_fname = tag[0]
+        if type(tag) is Tag:
+            this_fname = tag.rel_fname
+        else:
+            this_fname = tag[0]
 
         # ... here ... to output the final real entry in the list
         if this_fname != cur_fname: