For a long time French chefs didn't really "get" burgers. The model of a sandwich as a full meal doesn't really mesh well with French culinary theory and so it took foreign restaurants to build an audience (French burgers have since caught up and then some).
I still dream of getting the seed capital to start my beach burger shack, The Burgers of Calais...
As a french I have never heard of anyone considering a burger as a snack, like a bag of chips, and not as a meal.
Do you use a burger as a side to something else? Like you would eat it with a kebab instead of fries? Or is it the same for the kebab?
I don't think you can select a meal in a restaurant, then have a burger instead of fries/salad as "accompagnement". You will also not find a burger in the "starters" section on a menu.
I don't know how old you are but I'm talking about 20 years ago. There is now a menu category ("snackings") that handles grilled items but that wasn't there in the 90s and early 00s, and it was the encroachment of brands like McDonalds and Cinq Mecs that made brands like Big Fernand and le Camion qui Fume possible (not to mention expanding Quick's menu).
In Montenegro, McDonald’s has failed back in 2003, albeit at a small scale. McDonald’s also failed in Macedonia in 2013, this time the scale was non-trivial, 7 restaurants.
I often get caught out by this in France because I usually eat a late lunch in the UK and France is 1 hour ahead. You are cutting it fine if you start trying to find somewhere to eat at 1:30pm and by 2pm you’ve had it, game over. Suddenly the only option is Macdonalds and you know you’ve failed when you’re eating a lukewarm burger in a slightly seedy fast food restaurant; for some reason every time I’ve ended up in a Macdonalds in France it was pretty dirty.
McDonald's changes the recipes based in the country. In Italy you can find sandwiches with prosciutto and parmesan and they often use different buns than the soft, sugary ones.
Food places sell identity more than anything. Food quality just needs to be good enough to somewhat fulfill expectations implied by the price range. "We're an American behemoth selling a mockery of your national identity" certainly won't have it easy in Italy, no matter how well the pizza might be (never tried, I don't find that identity particularly appealing even as German visiting the United States). MacDonald's in France won't have any issue with identity: if you do feel like having factory food, what better match could there be? MacD certainly does not pretend being something it's not.