I was unaware that the LEZ zone in Antwerp also applies to foreign vehicles

The LEZ is a health measure. It therefore applies to all vehicles in the city, both residents’ and visitors’ vehicles alike. Foreign vehicles also have to register in advance, as the city does not automatically have access to the information relating to such vehicles. This means that foreign vehicles that meet the conditions of admission must be registered in the Flemish LEZ database via our registration tool. Foreign vehicles that do not meet the conditions of admission must buy a paid admission online or an LEZ day pass before entering the LEZ.

The LEZ is always indicated by zone signs F117 and F118 and by signs announcing the LEZ. These signs make sure that you do not accidentally drive into the LEZ.