Quick summary: this was a comfortable hotel, but felt overpriced for what it was and had a few flaws. It might be that it was the beginning of the July summer season when rates jump.
We spent one night here on our way back to Paris (catching the TGV the next day in afternoon in Bordeaux.) The hotel is in a modern building that is a few blocks from the ocean -- an easy walk to the beach, restaurants, shops, the casino, sites, etc. Parking is in a nearby secure lot. The art deco police station is across the street, but feels more secure than any problem with noise or commotion.
The hotel is comfortable and attractive, but feels like they have worked very hard to hold down costs through efficiency. There is only one person anywhere near the check-in desk, and is generally behind a wall with a window. That is, she only comes out when someone comes to the desk, with no other staff in sight. While it probably works well enough, it easily results in a backlog if a guest is involved with discussing travel advice, etc.
There are luggage trolleys to bring things to your room, but no bell staff that I could see.
Room 211 has twin beds, large windows, and feels roomy enough. (If my husband and I can't get a king bed, we prefer two twins to a queen.) There is pretty good closet space and a chest of drawers, and nightstands with drawers for the flotsam of life. Watercolors of jazz-themed dancers decorate the walls. In-room safe, flatscreen TV, and minibar.
Some issues: this had to be the dimmest room lighting I've seen in a long time, and is particularly annoying in what should be a modern hotel. The bedside lighting was pitiful. (More money-saving?) Also: I am not fond of the duvets on the beds that are increasingly found at hotels. To me, they are always much too warm, and this place was no exception. I later discovered blankets in the closet and should have requested a change in bedding.
Finally: a wake-up call never came. This is why I also set my iphone.
The bathroom feels a bit camped, but has a tub/shower combo. Okay towels and toiletries.
There is a nice bar and casual restaurant area, but we had drinks and ate in other locations. Free wifi in the lounges. The decor throughout the hotel is sleek, colorful, and modern, including the public rooms at the elevator on each floor.
The housekeeping was excellent. The desk staff were helpful and professional when contacted.
To avoid confusion, note that there is another Mercure Hotel nearby - Mercure President. It seems like a more elaborate hotel with a spa, etc.
So: while this was not a terrible stay, I'd probably give a different hotel a chance. The money-saving policies seemed a little too evident. Even so, I'd probably opt for San Sebastian over Biarritz.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC