PARIS » For more than a century, the lengthy school days of French children have been punctuated by a midweek day off, in recent decades for most children on Wednesdays, originally created for catechism studies.

The long hours and peculiar weekly rhythm have been criticized as counterproductive to learning and blamed for keeping women out of the full-time workforce, as well as widening inequalities between rich and poor because of the demands they place on working parents. Yet the Wednesday break has remained a fulcrum of French family life.

With all that in mind, the government of President Francois Hollande recently issued a decree introducing a half day of school on Wednesdays for children 3 to 11 years old starting in September, while reducing the school day by 45 minutes the rest of the week. In a country with a broad consensus in favor of shortening a school day that typically runs from 8:30 a.m. to at least 4 p.m. and sometimes longer, his government expected the plan to be less than controversial. It has not worked out that way.

Instead, the edict has sparked a wave of protest from France’s powerful teachers’ unions, parents’ associations and city governments, which say it was produced without their consultation, is short on details and fails to address deeper concerns about the middling performance of French schoolchildren compared with their peers in other industrialized countries. Thousands have taken to the streets in recent weeks in protest.

"The difficulties facing our students and our schools need pedagogical responses," said Sebastien Sihr, general secretary of France’s national union of primary schoolteachers. "We have to put an end to this magical thinking that just stretching the school week over four and a half days will improve students’ performance."

France’s peculiar school week dates to the creation of universal and free public schools in 1882 under Education Minister Jules Ferry. In a concession to the Roman Catholic Church, which until then had played a leading role in French primary education, the law reserved one day a week for religious instruction.

In today’s secular France, however, children of means spend their Wednesdays at music, sports or language lessons, while poorer families scramble for child care or place their children in subsidized public "leisure centers." For many parents — particularly women — the default solution is a part-time job.

Despite their four-day week and nearly four months of vacation, French children spend more hours in class than most of their European counterparts: 847 hours a year for third-graders, for example, compared with 750 hours on average for children elsewhere in the European Union. (In the United States, the average for students of all ages is around 950 hours.)

Yet, a 2009 assessment of high-school students in 65 countries by the Organization for Economic Cooperation and Development ranked France 21st in reading, 22nd in math and 27th in science. Dropout rates are on the rise, and nearly 40 percent of French 15-year-olds have repeated at least one grade — three times the OECD average.

"This is the only country I know where the adults work 35 hours a week, but they expect their kids to work more," said Peter Gumbel, a British journalist and a professor at Sciences Po who wrote a withering critique of France’s education system in 2010. "French kids are spending considerably more time sitting at their school desks than the average for outcomes which are generally worse."

He and other critics of the government’s plan say that its emphasis on a shorter school day fails to address more fundamental concerns, such as how and what French children are taught, how best to allocate limited education resources and how to recruit and retain better teachers.

Much of the problem, education experts say, is that France’s famously centralized primary school curriculum is overly focused on rote learning that discourages creativity and critical thinking. Fifty-nine percent of lessons for 7- and 8-year-olds are devoted to reading comprehension and math skills, compared with an average of 48 percent across the OECD. While standards for academic performance are high, teachers are given little flexibility to adapt their lessons to their students’ needs.

Expectations for far-reaching education reform were high after Hollande — who promises to hire 60,000 new teachers over five years despite France’s mounting budget crisis — narrowly won the presidency last May. But by choosing first to confront the four-day school week, Hollande, some politicians fear, risks alienating voters at a time when his approval ratings remain low, hovering around 44 percent.

Under the plan, the hours of instruction are to be reduced by 45 minutes on Mondays, Tuesdays, Thursdays and Fridays, though it is being left up to municipalities to decide whether to extend the lunch break or tack on 45 minutes of recess or other activities at the end of the day.

"This reform is so sensitive because it touches on people’s personal lives," Sihr said. The new government "had gold in their hands and they are in the process of turning it into lead."

Compounding the government’s efforts to sell its plan is the fact that it was drafted with little input from teachers, parents or local governments. Stakeholders said they first learned about the plan’s details from interviews that Vincent Peillon, France’s education minister, gave to the French news media.

"The whole thing started off very badly," said Valerie Marty, president of the Federation of Parents of Public Schoolchildren, France’s largest parents’ association. "We weren’t asked our opinion beforehand. Everything was already positioned by the minister before ever once being discussed."

In an interview, Peillon, a former philosophy professor, dismissed the backlash as a measure of the decree’s reach. "You can always judge the magnitude of change by the resistance it provokes," he said. "We have a habit in this country of always looking for excuses, but France needs to move forward."

Yet he conceded to early missteps in communication, and has begun holding town-hall meetings across France aimed at soothing tensions.

Still, some wonder if the minister’s efforts have come too late. A one-day walkout by more than 90 percent of Paris elementary schoolteachers last month was followed by a march of several thousand teachers and parents in protest of the plan. Unions have warned of more nationwide action and scheduled another strike for Feb. 12.

Opponents include scores of small-town mayors, who will be required to set aside additional money from their own budgets to provide extended after-school programs because of the shorter school day. Despite an offer of an extra $335 million from the national budget to municipalities this year, only a handful of major cities — including Paris, Dijon and Strasbourg — have publicly committed to making the change.

A growing number of communities, meanwhile, have said they will seek dispensation to postpone the changes until September 2014. The Education Ministry has agreed to accept such requests until March 31 and, according to French news media reports, half or more of municipalities may ask for the delay.

Peillon would not predict what percentage of schools he expected to make the change this year.

"It is not my role to be either an optimist or a pessimist," he said. "My job is to explain this reform as best as I can and to convince people to make the change sooner rather than later."

© 2013 The New York Times Company