We stopped by O Brasseur on our way back from hiking outside Thoiry to the west and just before…read morehitting CERN up briefly to learn as much about particle physics as can be understood by a non-physicist. As it's literally a couple minutes down the road from CERN - but on the French side of the border - it makes it a convenient / much cheaper option to eat at. O Brasseur has its own parking lot, but with only 5 non-handicapped spots that can get a bit tight depending on how well/poor others do with parking, you may find it easier to park down in front of the Carrefour that is slightly further down the road and walking back to the pub. Despite being near an international research facility, French is definitely the language of choice here; while the waitress who handled my check knew a decent amount of English, our main server and the man tasked at the bar when we came in knew very little. At least the menu is in English, which made it easy enough to point at when my (extremely rusty) French failed me. The ambiance inside has a typical pub vibe to it, but since there was some shaded seating outside, we ended up out there, enjoying the warmth a little but also the coolness of the shade and the breeze.
They do make their own beer here, so props to that. However, the selection is more limited (the English translations came out to lager, witbier, and amber ale - all with the same ABV somehow). I went with the 'limited edition', which I wish I had asked about...it was a Lambic, which was okay, but that kind of beer isn't up my alley. For the food, I would say that my wife's fish burger was actually a bit better / more distinguishable; the fish was very flaky and juicy, although that made it a bit tricky holding together the entire sandwich. My regular beef burger was pretty average - the meat was not as generic as some burgers I have had, but the patty felt a bit on the light side despite being a 6-ounce or so. Despite having bacon, cheese, and caramelized onions on it, none of those extras really came through. The French fries were decent, but the salad - topped with some heavy, mysterious white dressing that neither my wife or I could place - was just taking up space on the plate.
The prices are reasonable here, and the vibe is alright - and that's about where expectations should be kept. O Brasseur is a solid place for a casual bite, and if you are in this particular area, you might as well eat here...there aren't many other options from what I could see. I wouldn't go out of my way to end up here again, though.