Most of the food trucks near tourist spots are garbage but the ones that locals line up for are incredible. Honestly trust me on this - theres a crepe guy near pont saint louis who makes them to order not sitting under heat lamps all day

Also the falafel trucks on the left bank are way better than the touristy ones in the marais. Look for the ones with actual lines of french people not just tourists with cameras. Prices are like half what youd pay in a restaurant

Honestly some of my best meals in paris have been €8 from a truck. Just avoid anything near the eiffel tower or notre dame because those guys know you have no other options