Alone in Paris (1951)

Original title: Seul dans Paris

Henri and Jeannette Milliard, a newly married couple from Normandy arrive in Paris where they intend to spend their honeymoon. Unforfunately a wicket gate in the metro separates the couple. In panic, Henri looks for his wife across the capital. He ends up finding her at the hotel they were to put up. But it looks as if Jeannette has gone through some distressing adventure.