If you replace the fork with something new, you will end up also replacing the headset because the threaded portions are different on French bikes of that era (25x1 vs 25.4x24tpi). The stem will also need to be replaced because most French bikes used a stem quill/steerer that was 22.0mm and modern quill stems are normally 22.2.
If the fork blades are not kinked, the fork probably can be re-straightened. Maybe a local framebuilder can be of assistance?