It looks much like a straightened-out glazed, cream-filled donut flattened a bit on top.
Wikipedia says otherwise - a delicate pastry made with choux paste and filled with crème pâtissière (pastry cream or custard) and then topped with (often but not always) chocolate icing.
They are celebrating their 120th year in the food business. Their colors are black and white along with hot pink and deep fushia.These superb éclairs au café at the Patisserie Cador are more traditional. They reside in the perfect Louis XVI-style salon de thé just across from the Louvre at 2, rue de l'Admiral Coligny. A French éclair and you can eat in the appropriate setting!
Fauchon's Éclair Aquatique! I love going to the pool and French piscines are the best anywhere, and these remind me of Paris piscines. Gérard Mulot can be depended upon for classic French pastries. 76, rue de Seine in the 6th is open at 6:30 AM and on Mondays when most Paris patisseries are fermé (closed). You can not go wrong here. Green is the hot color in Paris this trip and especially in the patisseries. I love the way the pistachio nut (or the coffee bean) is planted neatly on top at Jean-Pierre Carton on 6, Rue de Buci, so there's no question what's inside.
éclair is the Fr. word for lightening. It's believed the pastry got its name because of the sheen when coated with confectioner's glaze. Antonin Carême (1784-1833), had much to do with developing French pastry and recipes. The "Paris Pastry Marathon", if such a thing existed, would beat out New York in a heartbeat. There seems to be a running battle who can come up with the most creative pastries in Paris. It would be fun to be a bystander at this marathon.
BONJOUR Paris ECLAIRS!