Cactus plants are native to the Americas, and the one below is growing on a street corner, across the intesection from a church, in Morehead City, North Carolina. It's called a prickly pear cactus.
When you think of American cacti, you probably think of the arid southwestern part of the United States, and not the humid Atlantic coast. But prickly pear species (Opuntia) are native to the East Coast from Florida north to at least New York. Another local cactus is a small plant we call a pear pad (maybe it's the same species). You have to be careful not to step on one when you are going around barefoot on sandy ground.
Above is a close-up of the same plant. The climate of coastal North Carolina is hot compared to Saint-Aignan's, and it's characterized not by persistent dampness but by heavy downpours of rain year-round, alternating with bright sunshine. I guess the cactus plants like that climate and the area's sandy soil.