There could possibly be a Season 4 if they can find a way to continue the story. It can be hard to come up with new plot ideas for a new season. It might be another year or two before we get another season, assuming Netflix has it pretty high on its priorities list.
I heard that the writing was done for season 4 but the french company was waiting for Netflix to green light it for production, one of the directors said if the series did get the 4th season cut then season 4 might get released as a comic book. (I tried to find the original source of this information, but the post seams to have been taken down)