We made a quick stop at this restaurant on the way back to our hotel from an unsuccessful trip to eat in Grand Case - we picked a bad night because we couldn't even park there! I noticed the L'Oasis sign from the street near our hotel and remembered seeing the name here, so we pulled into the parking lot and gave it a try. We were a little late by that point - around 8:30 or so - but the parking lot was empty and only one other group was in the restaurant. (We passed by on other days and it was busier, but never so busy you couldn't get a table or parking spot.) The area where this restaurant is located has a few other nice restaurants but is generally pretty quiet and a pleasant place to eat.
The service was very nice and fast (as you'd expect, given that it wasn't very busy) and our server was helpful in giving us tips for things to do and places to go around the island. She must have been the "new" French waitress that I've seen other people mention here - she's great!
It actually pains me a little bit to only give 4 stars - I'd give 4 1/2 if I could - but I have to compare it to the French restaurant we ate at later (L'Tastevin) and it doesn't really hold up to that. But it was still very good. I ordered the onion soup to start (I love to just see "onion soup" rather than "French onion soup" on a menu - that's how you know you're eating at a French-owned place), followed by the money-saving spaghetti bolognaise and then the creme brulee. My wife ordered the tagliatelles carbonara. All of our food was good, though the standout was the carbonara, which had real, thick bacon in it and a *lot* of it. My bolognaise was a little bit bland, but I realize this is probably not their specialty. The onion soup was made with the regular baguette bread they serve as table bread and didn't have that melt-in-your-mouth cheesy bread thing going on that the best French onion soups do, but it was tasty. The creme brulee was excellent - I couldn't get enough of the charred crust on top, which had a deeper flavor than most other creme brulees I've had. (They may use a different kind of sugar.)
Overall it was a really pleasant dining experience; quiet, good food, good service.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.