You can say the same thing about just about any opening. But we have got to call openings something, and so a name tends to stick at some point. It may not relate to the very first time that the opening was played, but it could be the first time that the opening was noticed by serious players or was played at the highest level with any success.

Here we have a high profile game between two of the most pre-eminent capital cities at the time. And the French team wheel out an opening that may have been played before by patzers but which wasn't taken seriously by anyone else. That fount of all knowledge Wikipedia says that one of the French players came up with idea of 1...e6:

"The French Defence is named after a match played by correspondence between the cities of London and Paris in 1834 (although earlier examples of games with the opening do exist). It was Chamouillet, one of the players of the Paris team, who convinced the others to adopt this defense"

And what is more, the Parisian team wins quite handily with their "new" opening.

"Cercle de Philidor of Paris had sent a challenge to London in 1822 but no match occurred. A new challenge was made on 29 i 1834. The Westminster Chess Club accepted and each side entered 50 pounds. London mailed the first move in February 1834. The Channel could be crossed by a steamboat. Paris' team met at 48, Rue Neuve Vivienne and had to answer in a fortnight. Pierre de Saint Amant led the Frenchmen."

<1.e4 e6>

"The name French Defence was given after Paris had won this game. Actually, the first move had been applied in Antwerp - Amsterdam 1827-9 (in which Black won), but the name Dutch Defence was used for another opening later."

This file gives the 27-move version, by the way.

The notes for the other game in the match (Paris vs London, 1834) indicate that it ended in October, 1836, which confirms <Once>'s speculation about the differing dates.

<Sep-04-08 Kink: There was, according to the chess history archives, two games played between these clubs. France won 2 - 0. Yet I cannot find a record of the other game anywhere. Does anyone know where I may find it?>

(2) Even if the English team was using black-colored pieces, they were "white" because they moved first. The color of the physical pieces on the board doesn't matter. (and they were playing by correspondence anyway).

6.♕e2+: <This move by white is a mistake. This check brings out a black piece and places the queen in front of the king, an often precarious position.>

8.♗e3: <By playing this move white wishes to defend the pawn which took the gambit of the queen,> [sic; perhaps referring to the fact that the c5 pawn was threatening white's queen pawn] <which is a risky defense. Better would have been to castle and let go of the pawn.>

9.♗b5: <This is a poor move which only helps to free the opponent's game.>

10.♘d4: <By bringing their knight to this square, white thinks they shall win a pawn or force black into a defensive move; they are again mistaken as the following moves shall demonstrate.>

11.♗xc6: <Had white taken the knight with their knight, black ought not to have recaptured but bring their queen to her knight's third square;> [i.e. b6] <with this move they would have regained their pawn with an excellent position.>

12.c3: <White cannot take the pawn with their knight, for if they did, black would win a piece by playing their queen to her knight's third square.>

14.♕d3: <Here it can be seen how precarious the queen's placement in front of her king was. With this move, white, in bringing their queen to her third square, plays quite poorly once again; it would have been better to bring her to her second square.>