Because Les Pennes Mirabeau is so close to the Lagoon - L'etang de berre, are mosquitos more of a problem in summer than further along the coast?
The short answer is Yes, this and the whole of the Camargue is basically marshland - paradise to mosquitoes , as is all stagnant water. And I hear the dreaded Tiger Mosquito has been spotted. They are less prevalent on the coast, disliking sea breezes. But just one mosquito buzzing around you at night is as bad as a whole swarm. Buy repellent and those bands you can put around your wrists and ankles - their favourite parts of humans.
Ed is absolutely right, and they are often very localised: a pool of stagnant water can be just a corner on the roof above your appartment. I am fortunate in that they seem to prefer my wife to me, however its not a solution I can recommend to others. A couple of plug-in repellants, plus a room spray before you go out, is fairly efective in keeping down the little blighters, plus a rolled newspaper and steady aim.Edited: 7:39 am, April 15, 2013
The good news is that if you hear them buzzing they aren't malarial. :) If that helps...
When we had a flat in Mont Boron, Nice, mosquitoes were quite a nuisance but since we moved three miles or so to Villefranche I have never seen or heard one.