French Kiss (2011)

A successful business man (Frédérick) is going through a series of insignificant adventures and one-night stands. One day, he starts flirting with Juliette. She mistakenly thinks that he is Robert, an ex-colleague, so he plays along to get closer to her. His perception of relationships evolves, but he keeps lying to Juliette to not risk loosing her. What seems to be a white lie eventually becomes uncontrollably problematic.