Differences between North and South coasts in France

My boyfriend and I are planning to meet my sister and her boyfriend in Paris three weeks from now. Then we will start exploring the country. Although we plan to see many places, most of the time we will spend on French coast. What are differences between North and South coasts in France?

Well, Normandy & Brittany have rugged coast, sandy beaches, quiet little harbor towns and rolling hills. You can find many Neolithic sites there. The atmosphere there is different from the rest of the country since you may still feel the Celtic influence. Temperatures of the air and sea are cooler. On the other hand, south coast is truly a Mediterranean type of coast with everything warm and nice about it. My definite choice is the South coast of France, somewhere around Nice, Cannes or St Tropez.