When dancing together in the closed restaurant near the beginning, Charles Boyer is clearly wearing shoes designed to make him look taller. Note the high heel and thick soles. In close-ups, he has on normal men's dress shoes instead. (Interestingly, in the stacked shoes, he's only a few inches taller than the barefoot Jean Arthur, suggesting that at least one of them lied about their heights throughout their careers. She's on record as 5'3" and he's on record as 5'9".)
The happy ending of the movie between Paul and Irene is pure "Hollywood", because they know nothing of the confession that Bruce wrote admitting he killed the chauffeur, so not only is Paul is still the correct suspect wanted for a murder in France he was framed for but also still believes he killed a man.
Further, in another complicating wrinkle the couple knows nothing about, the police prefect had already advised Bruce the courts would never pursue a charge against the chauffeur's killer if he was ever correctly identified, because it involved defending a woman's honor. So Bruce knew that Paul - who had finally come forward in returning to France to defend an innocent man - was not going to be tried (even for manslaughter, never murder, as the death had always been accidental, not intentional). But neither Paul nor Irene knew he'd be in the clear even admitting his role).
Further, in another complicating wrinkle the couple knows nothing about, the police prefect had already advised Bruce the courts would never pursue a charge against the chauffeur's killer if he was ever correctly identified, because it involved defending a woman's honor. So Bruce knew that Paul - who had finally come forward in returning to France to defend an innocent man - was not going to be tried (even for manslaughter, never murder, as the death had always been accidental, not intentional). But neither Paul nor Irene knew he'd be in the clear even admitting his role).