FRANCE'S extreme-right National Front has experienced peaks and valleys this year, but the general trajectory of the anti-immigrant, France-for-the-French political party of Jean-Marie Le Pen continues its climb up.After he sided with Iraq and a noninterventionist position on the Gulf war, Mr. Le Pen's popularity tumbled - much to the relief of France's traditional right, from whose followers Le Pen's National Front (FN) has generally culled its support. Now a recent poll shows that one-third of the French share the basic ideas espoused by Le Pen, up from 18 percent a year ago and 16 percent in 1989. Identification with the party jumps to 38 percent when the question is limited to the FN's ideas on immigration. The problem is that, up to now, with little more than Le Pen's periodic but generalized anti-immigration diatribes to go on, it has been hard to specify what the FN's policy on immigration is. That changed last week, however, when the party published a 50-point program to "settle the problem of immigration." The measures include granting French nationality at birth only to children of "blood" French; reviewing all naturalizations granted since 1974; installing strict foreigner quotas in public schools; blocking construction of mosques and Koranic schools; ending new immigration by revoking the family reunification policy; requiring companies to target immigrants when cutting jobs; cutting off immigrants from social benefits; and swift deportation of illegal, unemployed, or criminal immigrants. To end all "false tourism," the FN would require visitors to France to post a hefty bond - Le Pen has spoken of 100,000 francs, or about $18,000 - to make sure they leave the country. The party's second in command and author of the 50 propositions, Bruno Megret, says this measure would not apply to Europeans or other people sharing a common culture or religion. WHAT remains to be seen now is if translating its nebulous but cantankerous rhetoric into propositions will boost the FN's standing. The party's general tenor foreseeing doom for a traditional, "French" France fits well with public malaise over high unemployment, crime, and other domestic problems. Whether these same French will identify so closely with the FN's specific program is perhaps something else. "The shock wave caused by the 50 propositions" of the FN "is salutary," says Franz-Olivier Giesbert, a political columnist for the conservative Paris daily, Le Figaro. "Without realizing it, the FN's No. 2 man has just rendered a fine service to the parliamentary opposition," the traditional right. Indeed, leaders of the French right voiced what were among the most categoric condemnations of the 50 propositions. "Fascist,racist," and "xenophobic" were among the words employed by conservative politicians in response to the proposals. "They're a reminder of the darkest days of Vichy," said one, referring to France's collaborationist government during World War II; while a centrist leader added, "When will they propose the wearing of the star? a reference to Nazi anti-Jewish measures. Yet not all observers are convinced the FN's latest project will hurt the party's standing. "Many of the strong third or more of the people who say they agree with Le Pen on immigration don't necessarily hear or care about his specifics," says Colette Ysmal, a political scientist at the Political Studies Institute of Paris. "They are people who believe everything is going poorly," she adds, and are looking for a place to lay the blame. Another trend is that the traditional right, in a bid to win back supporters lost to the far right, has adopted some of its proposals. But that, in turn, says Mrs. Ysmal, only makes the FN's position appear respectable. "It was Giscard who dipped into the FN's program," she says, referring to former President Valery Giscard d'Estaing's recent proposal to stem the "invasion" of France by limiting nationality at birth to those of French blood. Commenting on the initial uproar over his proposals, the FN's Megret said the mainstream right "criticizes our measures today, but tomorrow they'll try to claim them."