The correct answer is - Marseille.
Marseille is one of the biggest and most important ports on the Mediterranean Sea, and not just nowadays, but it has a long history, pretty much from its forming till nowadays in continuity to be one of the most important ports in this part of the world. Through this port is exported pretty much everything that France produces, from agriculture products to electronics, and they are shipped around the globe. Most of the economy of the city is based on the port itself and around it.