Le Pen, leader of the National Front who shocked France by finishing second behind President Jacques Chirac in the 2002 election, recently attended a show by controversial comedian Dieudonne M'Bala M'Bala.
The black comic was fined by a French court for anti-Semitic comments in 2004.
Asked on BFM radio whether it was Dieudonne's anti-Semitism that he found funny, Le Pen responded: "Yes, that can also be funny. There should be no subject that escapes criticism or irony. It all depends on how it is treated."
"You know the people who mock Jews the most are Jews themselves. There's a Jewish form of humor that is very famous and well-known."
Le Pen, who received 16.9 percent of votes in the 2002 election, was convicted and fined in 1990 for inciting racial hatred and for saying in 1996 that the gas chambers used by the Nazis were "merely a detail" of World War Two.
He faces another trial next year for saying in 2005 that "the German occupation was not particularly inhumane". In June, he said the French soccer team had too many black players.
The 78-year old appeared to have cut down on xenophobic rhetoric in recent weeks. This was seen as part of a drive led by his daughter, Marine Le Pen, to attract voters.
A new campaign poster features a woman apparently of immigrant origin, rather than the usual picture of Le Pen himself. The party has also softened its line on abortion.
Recent polls have shown increased support for the National Front, a sign that the effort may be working, although he is lagging behind Socialist presidential hopeful Segolene Royal and the likely candidate from the ruling UMP party, Interior Minister Nicolas Sarkozy.