THERE WAS something gauche in more senses than one in George Bush's call on Francois Mitterrand. The vice president paid the administration's respects to the new French government, but he also expressed American "concern" that Mr. Mitterrand has put four Communists in his cabinet. To this Mr. Mitterrand responded in a very correct fashion, saying merely that "France's policy is that of France and will remain that of France." But was it really necessary for the United States to lay its jitters so publicly at Mr. Mitterand's door?

In case you missed it, Mr. Mitterand, a Socialist, won big in France's presidential and parliamentary elections. He decimated the Communist prsidential candidate, and in the National Assembly elections his party's margin lets it govern without need of any Communist or other-party support. This is awfully good news. Foreigners as well as Frenchmen have worried for years -- not without reason -- about the Socialists' dependence on the Communists. Having removed this albatross from the neck of the non-Communist democratic left, however, Mr. Mitterrand faced the tactical problem of what to do with the Communists. The still are a certain force to contend with, especially in the unions. His not unreasonable decision: to try to co-opt them, at least for a while, by assigning them four minor cabinet posts, our of 44.

But, administration officials mutter, the United States owed it to its non-Communist partners in Italy, and in other Mediterranean countries where Communist parties are strong, to demonstrate its principled opposition to any Communist Party's even partial access to power. There is something to this, but not everything. The spectacle of American indifference to Communist participation could be harmful, but the vice president of the United States need not have been deputized to make that point at the Elysee Palace. The situation of each European Communist Party is different. The French party, for instance, has never been anything but a crude, narrow opposition force of a Stalinist stripe. The Italian and Spanish parties, to name two, have very different traditions and political contexts.

In act, the participation of Communists in the Mitterrand cabinet may not be the real source of the Reagan worry. The administration is simply uncomfortable with governments of the left. But it is hard to say that to the head of a friendly democratic state who is on record as a firm opponent of Soviet expansionism and who has just won a sweeping popular mandate.