My 5 year old daughter is being taught French in school and she hardly remembers anything. Does it make sense to teach foreign language if the parent doesn't know the language?

Just like any other language be it Hindi or Marathi your child will have to put in a little effort towards it. Childrens minds are like sponges.They can retain a lot more than we can believe. Maybe she is not so interested in the language because she does not hear anyone around her speak it. You should try to encourage her a little more and maybe learn a few basics of the language yourself.