diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f2a444..d8b55ba 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Fixed
 
 - Do not mistake "océan indien" as IN
+- Support for Saint-Martin (France) postcodes
 
 ### Dependencies
 
diff --git a/geoconvert/convert.py b/geoconvert/convert.py
index 3ae2cf0..d66c9c5 100644
--- a/geoconvert/convert.py
+++ b/geoconvert/convert.py
@@ -281,6 +281,10 @@ def fr_postcode_to_dept_code(text):
             else:
                 return "20B"
 
+        # Saint-Martin
+        if postcode[:3] == "970":
+            return "971"
+
         # Other cases
         for code in (postcode[:2], postcode[:3]):
             if code in fr_departments.values():
diff --git a/tests/test_subdivisions/test_france.py b/tests/test_subdivisions/test_france.py
index d92fb58..cab4b88 100644
--- a/tests/test_subdivisions/test_france.py
+++ b/tests/test_subdivisions/test_france.py
@@ -172,6 +172,10 @@ def test_fr_address_to_dept_code(self, input_data, expected):
             ("Rue de la Réunion, 75000 Paris", "75"),
             ("Rue de l'Orne, 44800 Saint-Herblain", "44"),
             ("D7, Sainte-Luce 97228, Martinique", "972"),
+            # Saint-Martin postcodes
+            ("Code postal 97150", "971"),
+            ("Code postal 97051", "971"),
+            ("Code postal 97080", "971"),
             ("99999", None),
         ],
     )