I love lait fermenté, its a real delicacy, normally I have to travel to the Arab market to buy it and its a real treat when its on the shelves at Lidl as a promo.
I suggest that you try to embrace the différences and treat buying food as a voyage of discovery, no use hankering for cheddar cheese and English tea with non homogenised full cream milk, all of which you will (and it sounds like have) find from time to time when you can celebrate like I do when I find lait fermenté.
Speaking for myself, its not hard to adapt.
Editted, it is intended for drinking like a yoghurt drink, I like to use it on muesli. For sauces I use cr^me fraiche but lait fermenté would do the same job, if you would not put sour cream in your tea you should not use lait fermenté.
My mistake that I still make when hurried even after a decade is to think that lait écrémé is full cream milk, now at one time I thought thats what the word meant, i know better now so possibly its the colour of the packaging that throws me.