Several countries such as Canada and Australia have working holiday arrangements with France. You are able to work for part of your stay in the country in return for an extended visa. If there is no such thing availble for your country, then there are other options to pursue.
If you love working outdoors, then consider seasonal work such as a deck hand or ski instructor in the Alps or on the Cote d'Azur. People are always looking to hire new help or knowledgeable professionals as the seasons change and workers leave. Keep in mind that it is difficult to get this kind of work if you are American due to tax reasons.
Au pairing is one of the most popular seasonal jobs for young men and women. You will live with a family while providing them help with their children in exchange for meals, a small allowance, and a place to live. You will also be able to take French lessons at a local language school. You can find families through agencies or even through Craigslist. You can also find families at places like the American Church in Paris or the FUSAC, a monthly English newspaper. English speakers are some of the most sought after au pairs. Thus, it will not be hard to find a contract if it is your native tongue. Do not be afraid to put yourself out there if you want a job working in France as an au pair.