Waving banners and shouting slogans demanding freedom in Poland, about 50,000 marchers clogged the streets of the Montparnasse neighborhood here Monday evening. The ruling Socialist Party led the demonstration, and a wide spectrum of leftist unions and political parties followed.
But there were two conspicuous absences: the French Communist Party and France's largest union, the communist-run General Confederation of Labor (CGT).
The huge march, organized in less than 24 hours, highlighted the tremendous emotion with which France has reacted to the events in Poland. Moreover, it vividly demonstrated the deep divisions within Socialist President Francois Mitterrand's ruling leftist coalition.
The rally marked the first time in 15 years that all of France's labor groups , except the CGT, have banded together. The size of the rally also was impressive. Two weeks ago a carefully planned demonstration against US intervention in El Salvador produced only a few thousand marchers.
''Out of the 100 or so members in my party group, we got only about 10 out for the El Salvador demonstration, while here we have 25,'' said Guillaume Doval. He is Socialist Party secretary for the 14th Arrondissement of Paris.
The government itself has been cautiously circumspect in its reactions. The Polish crackdown has put the Mitterrand government, which is dominated by Socialists but includes four Communist ministers, in an awkward position.
Foreign Minister Claude Cheysson said France would do ''absolutely nothing'' about the events in Poland and stressed that there had been no external intervention. Prime Minister Pierre Mauroy was slightly more critical, warning ambiguously that any prolonged interruption in the liberalization of Poland would lead to ''grave consequences.''
No Socialist minister participated in the demonstration, but the pro-Socialist press made its feelings absolutely clear. ''Hope assassinated,'' headlined Le Matin under a huge, sad-looking face of Lech Walesa. ''The shame,'' blared Liberation in denouncing not only the events in Poland, but also the French government's limp reaction.
The papers of the conservative opposition were just as strong. ''Poland gagged,'' declared Le Quotidien de Paris.
In contrast, the Communist journal L'Humanite blamed Solidarity for the crackdown and urged the French to do nothing to inflame the situation.
''The excesses of Solidarity have ruined the hope which was born,'' wrote Yves Moreau in the lead editorial.
The French Communist Party has long supported Soviet foreign policy actions, including the 1968 invasion of Czechkoslovakia and the 1979 invasion of Afghanistan.
Moreover, several unions associated with the CGT broke with their leadership and marched in Monday's demonstration. ''There were some Communists in the group who disagreed with our actions,'' Pascal Nurnberg, secretary of the printers' union, said. ''So we went ahead without them.''
Many of the French were not so lenient in their appraisals of Communist nonparticipation, however. ''We carry a heavy responsibility in this affair,'' Le Quotidien wrote. ''We have accepted and we still accept - this is especially true for us French - that the enemies of freedom, that is, the directors of the French Communist Party, accomplicies in Soviet tyranny, are seated in our government.''
Intellectual Bernard-Henri Levy deplored ''the shame'' of Mr. Cheysson's ''cynical'' statements and said it was ''inconceivable'' that Communists in the French government continue to address the Polish working class.
This extraordinary passion in France over the events in Poland is also a result of the dear spot Poland holds in the French heart. History entwines the two countries: Since the 18th century they have often been tied by military alliances; in the 19th century large numbers of Polish workers migrated to northern France to man the coal mines there. Shared culture has tied the knot tighter: France has been the adopted home of such Polish artists as Frederic Chopin and scientists as Marie Curie.
Poland's ''summer'' of the past year has received headlines here constantly, and Lech Walesa, Solidarity's leader, has become a hero.
But now the dominant mood here is anger, as evidenced in the papers and the cries at the demonstration.
There is no sign, however, that the split between the Communists and Socialists over the Polish issue will force the Communists out of the government. Prime Minister Mauroy said there was ''no difference of sensibility among government ministers.'' A few hours later, though, he wriggled a bit under the weight of his own words and said that he would have been on the streets of Montparnasse if he were not a government official.