While the movie doesn't precisely match your description, it has these key elements:
* Bomber Pilot: The protagonist, Frank Towns, is a skilled bomber pilot.
* Shot Down: The B-17 bomber he flies is shot down in the Sahara Desert.
* French Resistance: The survivors of the crash encounter a French resistance group.
* Romance: Frank develops feelings for a woman named Jacqueline, who is married to a member of the resistance.
However, "The Flight of the Phoenix" focuses on the survival and the rebuilding of the crashed plane rather than a romantic relationship.
Do you have any other details you can remember about the movie, like the actors involved or any specific scenes? This might help to narrow down the possibilities.