The French love their onions. Oignons blancs (white onions), yellow oignons jaunes (or paille) and oignons rouges (red onions) are available year round. See here to learn how to cut them up like a French chef.
Most of the year (but rarely in December—February) they also sell spring onions (scallions), which go under several names: cébettes, oignons nouveau, oignons verts, oignons de salades, oignons blancs or ciboules. Don’t confuse them with aillets.
échalion, échalote: an elongated yellow onion that looks like a big shallot (échalote) only isn’t. It is also known as a cuisse de poulet (‘chicken thigh’), as in Cuisse de poulet du Poitou.
Image by inra.dist