Be careful! McDonald's french fries are NOT Gluten-free! I don't know what else they fry in the same oil (possibly nothing?) but here is the ingredient list directly from McDonald's website:
Potatoes, vegetable oil (canola oil, hydrogenated soybean oil, natural beef flavor [wheat and milk derivatives]*, citric acid [preservative]), dextrose, sodium acid
pyrophosphate (maintain color), salt. Prepared in vegetable oil (Canola oil, corn oil, soybean oil, hydrogenated soybean oil with TBHQ and citric acid added to
preserve freshness). Dimethylpolysiloxane added as an antifoaming agent.
CONTAINS: WHEAT AND MILK.
*(Natural beef flavor contains hydrolyzed wheat and hydrolyzed milk as starting ingredients).
They're not gluten-free or dairy-free. In fact, they're not even meat-free.