"They should first clean out their own house," he said.

The bid to exclude the two political chieftains was firmly opposed by Knoll's son Daniel.

Le Pen and Melenchon, political rivals and not in the same spot in the march, both were pushed and insulted with cries of "get out!" and "go home!" Shouts of "Nazi" were hurled at Le Pen, whose father and the founder of her National Front Party, Jean-Marie Le Pen, has been convicted of anti-Semitism and racism. She has since broken ties with the elder Le Pen.

Le Pen's bodyguard and her entourage formed a protective ring around her before riot police cut a corridor for her to leave.

Noting that Knoll's son, Daniel, had said he wanted to encourage national unity and that everyone "without exception" was welcome at the march, Le Pen said of the insults: "I find the behaviour here undignified toward the [grieving] family."

"Her son said he wanted everyone there, so we are here," she said.

Daniel Knoll, looking sad and tired, later bemoaned the hateful divisions at a march meant to unite.

"Today, we all should have been united, all of France," he said on BFM-TV. "Who cares which party? I could care less ... It's inadmissible."

Melenchon said "we did our duty" by coming to show compassion, adding that the real subject of the march was "this woman killed barbarically."

The march followed Knoll's funeral, where President Emmanuel Macron had showed up unannounced. The President had already mentioned Knoll in a speech at a military ceremony to honour a gendarme, Arnaud Beltrame, as a national hero for saving the lives of hostages in an Islamic extremist attack last week. Macron decried the "barbaric" views that fuelled Knoll's killing as well as the extremist who killed four people in a rampage in southern France.

Knoll's attacker, he said, "murdered an innocent and vulnerable woman because she was Jewish, and in doing so profaned our sacred values and our history."

Earlier on Wednesday, vandals scrawled anti-Israel graffiti and ransacked the offices of a Jewish student group at the University of Paris' Pantheon-Sorbonne campus. Sacha Ghozlan, president of the French Jewish Students Union, said it was unclear who was behind it.

Prosecutors have filed preliminary charges against two people for murder with anti-Semitic motives in Knoll's slaying, including a neighbour Knoll had hosted regularly, according to her son.

Authorities have not released the names of the two men in custody but have said the chief suspect is a 29-year-old with a past conviction who lived in the same building.

Mireille Knoll was forced to flee Paris with her family at age nine to escape a notorious World War II roundup of Jews. After the war she returned to Paris and spent most of her life in the eastern Paris apartment where she was killed, according to her son.

The US Holocaust Memorial Museum urged French and European officials to "redouble efforts to combat the rise in anti-Semitism plaguing much of the continent."

France's government presented a plan earlier this month to fight racism and anti-Semitism, focusing on social media and prevention in schools.

AP