There is no French translation for this term, as the practice barely exists in French restaurants for many cultural reasons:
- It is an insult to cooks not to finish your plate.
- Kids were raised to finish their plate ("think about the other small children who have nothing to eat"), although that's probably not true anymore.
- It makes oneself look like a miser, or someone cheap.
- Large portions of food are sometimes denounced as a bad American symbol ("Dès que le doggie bag aura été popularisé, on pourra craindre le pire pour la France !", "As soon as the doggy bag is made popular, we can fear the worst for France!")
Most restaurants and some French people know and use the English term "doggy bag" though, but many people would just ask the restaurant to bag "les restes" (the remainings of your meal), without specifically naming the bag.
