IT IS OUR melancholy duty to point out that the French have misbehaved once again, this time egregiously, in the matter of Quebec. From time to time it pleases French politicians to toy with the idea of a Quebec that is an independent nation rather than a province of Canada. Quebec, after all, speaks French. This deliberate fanning of the sparks of Quebec separatism - which is to say, Canadian dissolution - is a most dangerous kind of meddling in another country's business. But the French, in this kind of cultural nationalism, are incorrigible.

Rene Levesque, the premier of Quebec, has been visiting Paris. The premier of France met him at the airport with an honor guard. Mr. Levesque was ushered into the National Assembly by the great ceremonial stairway that has not been used since the reign of Louis XVIII, a century and a half ago. He addressed the Assembly. He was made a grand officer of the Legion of Honor. He was widely lunched and dined.

The lavish arrangements and the protocol were a game in which his hosts came, by fine calculation, within the last hair's breadth of treating him as the head of an independent state. When he left, the French President, Valery Giscard d'Estaing, issued a communique hinting that Quebec can count on French support as it follows whatever road it might choose. Mr. Levesque intends to hold a referendum in Quebec on national independence within the next couple of years.

It's been 10 years since Gen. Charles de Gaulle, then president of France, gave him memorable cry, "Long Live Free Quebec!" At the time, Mr. Giscard d'Estaing seemed to think poorly of the gesture and speculated, not very privately, whether the old man was not losing his grip. But now Mr. Giscard d'Estaing is president, and a certain view of Quebec seems to go with the office. It does not escape notice, incidentally, that the French election will be held next March. The left is doing very nicely in the polls, leaving Mr. Giscard d'Estaing desperately dependent on the Gaullists. The dream of a worldwide chain of French-speaking nations, drawing inspiration from the mother country, is one that perennially warms hearts on the French right.

The conversation during Mr. Levesque's visit was evidently very elevated. The speeches were full of references of fraternal sympathies, cultural affinities, national destinies and that sort of thing. If Quebec should eventually choose to break away from the rest of Canada, its immediate requirements would, of course, be more mundane. It would need heavy financial support, investment and, possibly, access to new markets. There wasn't much about that in the French communique.