The theory behind the shorter workweek, as Mr. Jospin put it recently, is that ''growth will not suffice to create jobs, so a cut in working time is needed.'' In other words, it is vain to expect the pie to grow fast enough to feed everyone, so it has become necessary to divide it into smaller slices.

''It is our duty to bring hope back to this country and the priority of my Government's action is the creation of jobs, lots of jobs,'' Mr. Jospin said today.

France has suffered sluggish growth for many years now -- an average of less than 2 percent annually since 1981 -- and many economists argue that the country is simply overregulated to a point that discourages entrepreneurship and hiring.

But there is widespread resistance in France to what is portrayed as the ''Anglo-Saxon'' method of job creation: Lower minimum wages, diminished job security and sharp cuts in the charges and taxes that pay for social programs, including unemployment benefits and pensions.

In the United States, where people already work about 20 percent more hours per year than in France, the notion of a shorter week to create jobs tends to prompt skepticism. ''The problem with these ideas is that they preserve the fantasy that this is the direction in which to go,'' said Steven Englander, an international economist at Smith Barney here. ''France is not going to create jobs this way.''

The shorter week, with no loss of pay, formed a central part of the platform on which Mr. Jospin's Socialist Government was elected last June. But the Government appeared split and hesitant before proposing the law today. A few weeks ago Mr. Jospin suggested that a 35-hour week might prove ''anti-economic'' if adopted too quickly.

The Prime Minister, however, relies for a core of his support on public employees and labor unions that back the plan. Marc Blondel, the leader of one of the more radical unions, said today, ''The law on a 35-hour week should be adopted as soon as possible.''