ordinance, ordnance

Ordinance or ordinance means a local law or regulation--
There is a new ordinance against smoking in public buildings.
There is a city ordinance against dogs without a leash.

Ordnance or ordnance means cannon or other military weapons and their ammunition--
The army won the battle because of its innovative use of ordnance.
The new recruit was assigned to an ordnance and supply company.

Now that you know that, you can say--
"There is a local ordinance against having any kind of ordnance or military weapons, even as part of a war memorial."

Note-- "ordonnance" means the arrangement of the parts of a building, or the elements of a literary composition or painting--
His editor suggested that the ordonnance of the work made it difficult to follow.