[pavlov]

At least in the case of France, the point seems valid, and it's perhaps opposite of what you're assuming.

The modern French nation is actually a left-wing construct -- an intentional product of the French Revolution. The Kingdom of France was not really a unified nation-state as we understand them today. There were multiple languages and a rich spectrum of local identities. French subjects were not necessarily French-speaking: their native tongue could just as well be Provençal, Italian or something else, and the King didn't really care.

The Revolution triggered local counter-revolutions of people who didn't necessarily think themselves as French in the sense that the new government in Paris wanted them to. (The War in the Vendée was a particularly bloody local war even by Revolution standards: https://en.wikipedia.org/wiki/War_in_the_Vendée)

To counter the insurgencies and establish their new order, the Revolutionary authorities set about to explicitly design what a French citizen should be. The predominance of the French language was one element of this.

[aaron-lebo]

Napoleon (whose political views were across the board, but fairly right-wing) had more say about establishing the French state than any of the revolutionaries that had power before him. The Code Napoleon, for example.