All Cats Are Grey (2014)

This Belgian drama is about the special bond between father and daughter. Paul is a 46 year old PI. Dorothy is almost 16 and has an identity crisis when she finds out her father isn't her biological father. Her mother won't tell her anything. Paul doesn't know Dorothy but he knows that he is her biological father. One day he spots her on the street. He keeps an eye on her but doesn't have the courage to approach her. Until one day she approaches him to look for her father.