Is Haguenau located in a L.E.Z ?

No, Haguenau is not located in a low-emission zone.

Strasbourg, on the other hand, is located in an L.E.Z.

If you plan to visit Strasbourg with your own (non-French) car, buy a lifetime vignette (less than €5): https://certificat-air.gouv.fr/ (this site is in 6 languages) - If you rent a car: ask your rental company.

Want to visit Strasbourg without worrying about the L.E.Z.? Take the train ( https://www.sncf-connect.com/en-en ) there are 29 connections a day (30 min. journey, shorter than by car), it's easier than using your car.