Hello,
My adopted diabetic kitty, Bonbon, was obese when she went into rescue, and when she first came here.
She'd been on a dry diet all her life, and when she came here I transitioned her to low carb and lower calorie food to help with her weight loss. I also got some baby scales to weigh her on to monitor the weight loss so that it wasn't going too fast. (Weight loss needs to be done carefully in kitties, and especially carefully with diabetics...)
As well as feeding her lower calorie food I also added a little water to that to help her feel fuller.
Exercise seemed to help her too. I bought all kinds of toys for her, trying to find something that caught her attention and 'eventually' she did become more playful... And I got her a large catnip toy that she would grab hold of and kick with her back legs to give them a bit more exercise. She really didn't want to move off her favourite armchair at first, unless to eat or use the litter tray....so I moved those a bit further away so she had to walk a bit further, haha! ...I think part of the problem was that her joints had become stiff due to her not moving around. But her mobility has improved. And she can even run now if she really feels she has to!
There is a list of UK low carb foods, many of which should be available in France also (quite a few from Zooplus, for example). The list also shows calories per 100g.
And if you scroll right down to the bottom of the list there are a few foods there (requested by members here!) that are available in mainland Europe but not the UK.
Here's the link in case that list is useful for you.
Please just ask if you need more help.
https://docs.google.com/spreadsheets/d/1J5JpMe6TDXrHq_aTl9hUtHy6Gs9oRBqlz4nPGKxtySA/pubhtml
Eliz