Sorry, I know this is probably the wrong place for this but couldn't decide where to put it, so am putting here and in Chat.
I am taking my DD (15 months) to the south of France for a few days on Sunday, to crash IL's holiday. We will mainly be catering for ourselves but on the off chance we do eat out, can someone please tell me how to explain, in French, that my daughter is milk protein intollerant and cannot have any milk or milk derivatives in her food.
I am that I don't speak French and am fairly certain my FIL's won't stretch this far and DD will end up will a glass of milk topped with cream if he translates
You could also try "ma fille fait une allergie trèssévère aux produits laitiers, y compris les produits dérivés" or at least try to stress the word "allergie", to get people's attention.
"Pour des raisons médicales" is usually a good one, too.