Agaricus bisporus, champignon de Paris are the common white or light brown mushroom. France raises massive amounts of them (the French were the first to cultivate them, thanks to the Pasteur Institute which realized that the soil and manure had to be sterilized before planting the spores).
The vast tunnels under Paris, used to quarry building stone and plaster of Paris were one of the first spots to host mushroom farms, which is why they are called champignons de Paris (something from Paris also denoted quality as well). These days nearly all are grown in the caves of Saumur (along with pleurotes and shiitakes), which produce some 10 tonnes a yeaer, and where you can visit the Musée du Champignon
Originally all button mushrooms were brown until a mushroom farmer in Pennsylvania chanced on a white mutation in 1925; most button mushrooms sold around the world today are derived from this one fungus that marched to a different different. You can also easily find very large versions, galipettes or champignons à farcir— mushrooms for stuffing.
Image by böhringer friedrich