François Nascimbeni/Agence France-Presse

In Reims, a vote is cast during a test of an electronic voting machine made by Indra of Spain.

PARIS, April 3 — For France’s Socialists, among others, the coming presidential election could descend into a nightmare like last fall’s in Florida.

This is the first presidential election in France to use paperless computer voting. As many as 1.5 million of the 44.5 million registered voters are expected to cast their ballots electronically in more than 80 municipalities around the country.

But with election day less than three weeks away, opposition to the electronic voting machines has grown, in part because a small percentage of them are made by the same American company whose machines were involved in a bitterly disputed Congressional election in Florida last November.

“We have doubts about the reliability of these machines,” Gilles Savary, a spokesman for Ségolène Royal, the Socialist Party candidate, said in an interview. “I don’t want to lecture America. But we don’t want France to fall into the same Kafkaesque balloting as happened in the United States.”

Last week, the Socialist Party called for a moratorium on using the machines until their reliability could be determined. The party also wants a debate on the issue in Parliament.

“The fear shown by numerous voters faced with a system they don’t know runs the risk of keeping them away from the polls,” the Socialist Party said in a communiqué on Friday, adding that the risks of fraud and of “massive and undetectable errors” are very real.

Among the problems cited was the case of as many as 18,000 electronic votes that disappeared in a tight Congressional race in November in Florida. In February, Florida election officials announced that experts had concluded that poor ballot design, not the paperless machines’ hardware, had been at fault. Some people continued to argue that there must have been malfunctions, but that problems could not be found because the machines did not have backup paper trails.

In its statement, the French Socialist Party noted that two of the three types of machines approved by the French government, those made by Nedap of the Netherlands and ES&S-iVotronic, the company that made the machines used in Florida, had been “sharply disputed in countries in which they’ve been used.”

Nicolas Sarkozy, the center-right former interior minister running for president, is leading in the polls for the first round of voting, on April 22, followed by Ms. Royal in second place. Only the top two candidates make it into the second round, two weeks later. With a crowded field of 12 candidates and many undecided and first-time voters, every vote counts.

The potential 1.5 million electronic votes “is not insignificant,” said Vincent Feltesse, director of new technologies for the Socialist Party. “It’s an important percentage. We remember what happened the 21st of April.”

On April 21, 2002, the first round of voting in the last presidential election, the extreme-right leader Jean-Marie Le Pen staged a stunning upset. He edged out the Socialist candidate, Lionel Jospin, to take second place by fewer than 200,000 votes.

It is not only the Socialists who oppose the use of electronic machines.

François Bayrou, the centrist candidate from the Union for French Democracy party, said last month that it was necessary to “stop this evolution and suspend all use” of electronic voting, because the vote would not be completely reliable.

Some smaller party candidates, including those representing the Green and Communist Parties, also are demanding that the machines not be used. The governing Union for a Popular Movement, which Mr. Sarkozy heads, favors their use.

Each municipality has the right to choose whether or not it wants to go electronic. A number of cities and towns, including Grenoble, Beauvais, Saint-Denis and Sceaux, have said they are sticking with paper ballots on election day because of doubts about the new technology.

Cost is also a deterrent; each machine costs more than $5,300.

An organization called “Citizens and Computer Technicians for a Vote Verified by the Elector” has circulated an online petition to oppose all computerized voting in the election. It already has more than 38,000 signatures.

But the Constitutional Council, France’s highest constitutional body, defends the integrity of the new system. In a statement last Thursday it said that all voting machines had been authorized by the Interior Ministry and “have been declared in conformity with the Constitution.”

Some electronic voting machines have been used in regional and European elections in France since 2004, without problems, according to a senior Interior Ministry official, who spoke on condition of anonymity as is the tradition in his office.

About 80 percent of the machines scheduled to be used this month in about 70 municipalities are made by Nedap, which has had its own share of problems. Ireland spent more than $50 million on Nedap’s machines, but suspended their use in elections in 2004 and 2006 after doubts about their reliability surfaced.

ES&S-iVotronic is providing about 160 machines to be used in as many as eight municipalities. The Spanish company Indra is providing a smaller number of machines.

“We have an extreme amount of confidence in our machines in France,” said Rob Palmer, director of marketing and communications for ES&S-iVotronic. “Our machines have proven themselves in thousands of elections in the United States and elsewhere.”

Matthijs Schippers, director of election systems for Nedap, said: “The systems we have developed for France comply with all legal standards and regulations that are incorporated in French electoral law. The accusations have no factual basis.”

A number of towns are testing the electronic voting systems in dry runs intended to identify glitches and put their electorates at ease.

Last week in Reims, the capital of the Champagne region and one of the largest towns to sign on to electronic voting, 100,000 registered voters were given the opportunity to try the machines.

Only a small number of voters showed up. They voted on what kind of tree — june berry, golden bamboo, magnolia, photinia or rhododendron — should be planted on a main avenue undergoing renovation. No irregularities were reported. City Hall has yet to announce the winner.

Maia de la Baume contributed reporting.