When sailing in France, you will need standard equipement on your boat, as is usually necessary. The boat should have steering compass, hand bearing compass, log and depth sounder. Also most of the French marinas have VHF connections so all should respond to a call on VHF. Also it would be the best if your boat is equipped with GPS chartplotter and radar in order to make the sailing easier for you.
Another thing that is important when sailing in France is the weather. There are a number of different winds that blow all along the French coast. But there are two winds that predominate, the tramontane and the mistral. A tramontane is caused when a depression passes across the middle of France and the air escapes through Pyrenees and the Massif Central. Mistral blows when a depression passes over central France and cold air is blocked by the Alps and escapes along the Rhone Valley. Usually these winds are not that often during the summer, so you can enjoy your vacation.
Besides the winds another thing you should pay attention are thunderstorms, which are often in spring and autumn. Visibility is generally very good during the whole year. The fog is usually the highest in May, but in some areas visibility can be reduced by the smoke and emissions from industry.
Sea temperatures are lowest in January at around 11°C and the highest in August at around 20-24°C, while the differences in sea level are usually caused by constant strong winds.
You can check the weather forecast on web pages, radio chanells,newspapers and TV.
Some of the web pages are: