French large chain supermarkets are rubbish. Especially since they smell like a sewer when you walk in. Not surprising, as the fresh stuff has mould on it (as does Spain), The queues are too long and the range is meh. I also reckon they are 20% more expensive than UK and Germany.
UK is world leading and has been for over 20 years. As was Thailand when I was in supermarket research 20 years ago. I also worked on Woolworths and Coles in Australia. That was like going back another 20 years.
No doubt some people will say this is not their experience regarding France. When they do, I will go to my Carrefour and take some pictures of the mould for you. I might throw in a video of me queuing too if you are lucky. You will see that getting the product through the checkout fast is not a priority for the staff.
When I come back to the UK, I fill the van so I can avoid French supermarkets. Boulangeries are fine, as are small meat delis. It's the big brand supermarkets that need knocking into shape. Carrefour pulled out of Thailand after only a handful of years because the idiots filled the shelves with French produce. You couldn't make it up. Tesco, who I worked for in Malaysia on range assortment and category management for their first store, cleaned up in Thailand by buying Lotus and developing from there.
Some might argue the smell is authentic That is how fresh food smells. That does not add up at all. Local fresh fruit and veg stores in UK do not smell like someone dropped a massive frart at the door.
But the arrogance still filters through to the stores here in France. They think it is fine if I am queuing ten mins for a bottle of milk, which I am lucky to get, as it often does not arrive until late morning. Carrefour number 1, customer number 2.