Royan is nice quick stop if you travel around France, especially in the west (for example from Paris to Bordeaux, Bayonne or direction Spain).
It is located on the Atlantic coast and it beneficiate of a good climate protected by the river-mouth of the "Gironde". It is close to many lovely cities; Within 2 hours driving you can go to Bordeaux (south), La Rochelle (north), Cognac (east), Angouleme (east), and even Poitiers (north).
What is so particular with Royan is its architecture.
You like it, or you hate it but it is extremely particular. Approx. 95% of the city was destroyed by allies bombing at the end of the Second World War. So forth, the architecture of the city is totally 50s and it is worth seen if you never experimented this type of architecture. Do not hesitate to google (image) it, the church is extremely recognizable (was build to look like a boat, over looking the sea).
On the other side, you will be able to enjoy the best ice cream in the area (Glacier Lopez), a sea view in lots of hotels (request one! - or rent your own appartment with view - really popular accomodation), usually a great weather and more.
I personnally really like it and a lot of my friends do too. It is extremely popular among French who travel inside their country.