diff --git a/otbtf/utils.py b/otbtf/utils.py
index 5694772b2c6533c0405bf288838d101a5ba8edfe..729f771578ea8990435740cbb398f3da4fa20b0c 100644
--- a/otbtf/utils.py
+++ b/otbtf/utils.py
@@ -34,7 +34,7 @@ def gdal_open(filename):
     """
     gdal_ds = gdal.Open(filename)
     if not gdal_ds:
-        raise Exception("Unable to open file {}".format(filename))
+        raise Exception(f"Unable to open file {filename}")
     return gdal_ds