Obviously I've seen some pretty romantic scenes since taking up French (and thus taking up French movies) but this scene from Yvan Attal's Ils se marièrent et eurent beaucoup d'enfants ranks right below the final scene in No le dis personne (probably the most romantic scene in all of history.) This scene features Attal's partner, Charlotte Gainsbourg, who plays his wife in the film film. I don't think this clip totally captures the power of the scene--outside the film (which is streaming on Netflix) it looks like a really cool music video.
One thing about watching movies in another language is you really learn to pay attention to the acting--especially the second time around. I usually take off the subtitles after I've seen something once, and sometimes even before then. (I'm still not totally clear on the plot in Ensemble, C'est Tout.) So every little facial movement becomes significant in a way that it wasn't before.
In that vein, these are two beautiful faces doing beautiful work. The movie is mostly told from a male perspective. This was a really nice oasis.