Paris (CNN) Thousands of people marched through Paris on Wednesday evening to protest the killing of a Holocaust survivor in her home over the weekend, in what investigators are treating as an anti-Semitic crime.

Mireille Knoll, 85, was stabbed 11 times and her apartment was set on fire in the attack, French authorities said. Two men in their 20s have been arrested, one a neighbor of Knoll's and the other a homeless man, a judicial source told CNN.

An image of Mireille Knoll posted on the door of her apartment in Paris on March 27, 2018, after she was found dead.

Protesters marched to Knoll's home in Paris' 11th arrondissement on Wednesday, many carrying white roses in mourning for Knoll. Others held signs showing a yellow hand, which became an anti-racism symbol in France some years ago, above the phrase, "Don't touch my friend."

Dominique Moisi, co-founder of the Paris-based French Institute of International Relations, said he was marching to call for peace across the country.

"What we want is a kind of unity in the country, behind sanity, humanity, to proclaim the sanctity of life," he said.

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