(JTA) — French Prime Minister Manuel Valls, who last year called anti-Zionism a form of anti-Semitism, is likely to lose the Socialist Party’s primaries to a left-of-center challenger, according to several polls.

Benoit Hamon, a former education minister who has criticized Valls’ hardline politics — including Valls’ supports for banning some Muslim religious garb — on Sunday won the first round of the Socialist primaries with 36 percent of approximately one million votes cast. Valls came second with 31 percent.

However, Hamon came out as a clear favorite of a televised debate he had Wednesday with Valls, thereby increasing his lead dramatically among Socialist voters in the second and final round Sunday, according to a Harris Interactive poll conducted online among 1,952 respondents for the news site Atlantico.

More than 60 percent of the Socialist voters who watched the debate said support Hamon compared to 36 percent who said they would vote Valls. Among Valls’ supporters who participated in the poll, 63 percent said they thought he won the debate, compared to 92 percent of Hamon supporters who believe their man won it.

Of all respondents who said they would vote in the second round, 86 percent said they wish Hamon would win, compared to 25 percent who said they preferred Valls.

Valls is widely believed to be the favorite presidential candidate among the 500,000 Jews who live in France, a nation of 66 million people. He is married to Anne Gravoin, a Jewish musician. In 2011 he said that his marriage connected him “in an eternal way” to Israel and the Jewish people.

Last year, Valls reiterated assertions he made previously on anti-Zionism, calling it during a speech “a synonym for anti-Semitism and hatred of Israel.” It was the first public statement of its kind by a presiding prime minister of France.

Both Hamon and Valls have expressed their opposition to attempts to boycott the Jewish state, which are illegal in France.

Hamon called in a televised interview last month the establishment of a Palestinian state the “best way of ensuring Israel is not attacked by its neighbors.” But in a 2014 interview, he said that supporting the establishment of such a state was the Socialist Party’s “best way to recuperate our electorate in the suburbs and the neighborhoods” – code for Muslim voters — “who did not support the pro-Israeli position taken by President Francois Hollande.”

Hamon has criticized Valls, too, for “giving in to Israel.”

The winner of the Socialist primaries will run in May against several presidential candidates, including Francois Fillon, a rightist politician for the party of former president Nicolas Sarkozy; Marine Le Pen of the far-right National Front party and Emmanuel Macron, a centrist independent.