When Farida Trichine and 11 of her friends burst into a French supermarket in 2009 and began applying stickers with anti-Israel slogans to vegetables imported from the Jewish state, she expected to be escorted from the store by police.

What she didn’t expect was to be convicted of inciting racial hatred and slapped with a $650 fine.

Three months ago, a court in Colmar convicted the 12 activists under a French law that extended the definition of discrimination beyond the expected parameters of race, religion and sexual orientation to include members of national groups.

What Trichine, who was wearing a “boycott Israel” shirt during the protest, saw as a protected act of political speech was being treated by the authorities like a hate crime.

“It’s surprising that our actions are considered a crime when the real criminals are the colonists, the butchers of Gaza,” Trichine said in a video message in 2011, soon after her legal troubles began.

Trichine, 54, is one of approximately 20 anti-Israel activists who have been convicted under France’s so-called Lellouche law. Named for the Jewish parliamentarian who introduced it in 2003, the law is among the world’s most potent legislative tools to fight the growing Boycott, Divestment and Sanctions movement, or BDS, and has catapulted France to the forefront of efforts to counter the movement through legal means.

“The French government and judiciary’s determination in fighting discrimination, and the Lellouche law especially, are exemplary for Belgium and other nations where discriminatory BDS is happening,” said Joel Rubinfeld, co-chair of the European Jewish Parliament and president of the Belgian League Against Anti-Semitism.

French authorities have acted aggressively in recent weeks to crack down on anti-Israel and anti-Jewish speech, most prominently by banning a tour by the comedian Dieudonne M’bala M’bala, who has been convicted multiple times of belittling the Holocaust and alleging that a Jewish mafia runs France, among other offenses. But the dragnet has also swept up BDS protesters whose actions have targeted Israel, not Jews.

Pro-Israel activists in neighboring Belgium are pushing for a similar law to Lellouche, hoping it might also put a dent in BDS activities in that country. No other countries have followed France’s lead.

In France, the official crackdown is sparking a backlash from activists who argue that the Lellouche law is too restrictive of free speech.

Before the convictions of Trichine and her associates, a solidarity petition by pro-Palestinian activists failed to garner more than 1,500 signatures. After the convictions, 51 groups — among them several labor unions and political parties with hundreds of thousands of supporters combined — condemned the verdict as “an unbearable attack on freedom of expression.” Three short documentaries have been made about the case, which has been covered in dozens of articles in leading French publications.

“These convictions are unconscionable,” Nicole Kiil-Nielsen, a French member of the European Parliament, said at a special session on the case in Strasbourg in 2011. “Governments are doing nothing to end Israel’s illegal occupation and the French court is wrongfully denying citizens from acting through BDS.”

Pascal Markowicz, the head of the BDS legal task force of the CRIF umbrella group of French Jewish communities, said the Lellouche law was enacted not because of the lawmakers’ desire to protect Israel, but because they sought to strengthen French republican values and counter sectarian tendencies. The law was passed in 2003, shortly after unprecedented gains by the far right National Front party in the presidential election.

The measure was designed to respond to a social climate of not only mounting anti-Semitism, but also anti-Arab discrimination and xenophobia. Nevertheless, it has been invoked repeatedly against anti-Israel activists. France has seen 10 trials against BDS supporters based on Lellouche.

Markowicz says the law is “the most effective legislation on BDS today.” “We had only one acquittal, so the statistics are looking good,” he said.

Elsewhere in Europe, in countries where free speech traditions are more robust, laws like Lellouche are a much tougher sell. But that hasn’t stopped pro-Israel activists from trying to fight BDS with existing anti-discrimination laws.

In 2007, the British University and College Union said it would drop plans to boycott Israeli institutions after legal advisers said doing so would violate anti-discrimination laws. Last year, a British court threw out a discrimination case against the union brought by a pro-Israel activist in what Jonathan Goldberg, one of Britain’s leading trial lawyers, called “a legal and public relations disaster” for pro-Israel forces.

In the Netherlands, legal efforts to curb the anti-immigrant politician Geert Wilders, a supporter of Israel, have been largely unsuccessful.

“The French legislation is effective there but would be too unpopular here,” said Gidi Markuszower, a prominent pro-Israel activist.

In recent months, the Netherlands has seen several large divestments from Israel, including the Vitens water company and PGGM, the country’s largest pension fund. Similar divestments were announced recently by the largest pension fund in Norway and Danske Bank, Denmark’s largest.

But in France, despite its reputation as a hotbed of anti-Israel activity, there has been no divestment from Israel of late, a fact Markowicz attributes largely to the Lellouche law.

Still, Markowicz acknowledges that the law is a double-edged sword, not least of which is the “I boycott too” campaign to support Trichine and her associates. The Lellouche law also precludes calls for a boycott against Iran over its nuclear program, requiring the Jewish community to take care in how it expresses itself on the issue.

Despite the costs, Markowics is willing to pay the price. As for the backlash, Markowicz says the issues are so removed from the lives of ordinary Frenchmen that it’s not a major concern.

“For us, BDS is a big issue, so we must fight,” he said. “But in French society it’s just not big enough of an issue to provoke a strong, popular reaction one way or another.”