French President Emmanuel Macron has condemned an antisemitic attack on an eight-year-old boy in a suburb north of Paris.

The boy, who was wearing a kippah, was reportedly pushed to the ground and beaten while on his way to an after-school class in Sarcelles on Tuesday.

He said his attackers were about 15 years old, AFP reported.

Local prosecutors said they were treating the incident as an antisemitic crime.

“An eight-year-old boy was assaulted in Sarcelles. Because he was wearing a kippah,” the French president tweeted.

“Every time a citizen is assaulted on the basis of his age, his appearance or his faith, the Republic as a whole is assaulted.”

“And it is the Republic as a whole today especially that stands alongside French people of the Jewish faith to fight these vile acts with them and for them.”

Et c’est toute la République qui se dresse particulièrement aujourd’hui aux côtés des Français de confession juive pour combattre avec eux et pour eux chacun de ces actes ignobles. 2/2

— Emmanuel Macron (@EmmanuelMacron) January 31, 2018

The attack came a day after a French Jewish community leader condemned a judge for not classifying the notorious killing of a Jewish mother as an antisemitic murder.

Sarah Halimi, 65, was tortured to death and thrown out of a third-floor window in April 2017.

A 27-year-old Malian Muslim, Kobili Traore, has been charged with intentional homicide.

But this week a judge rejected a prosecution request to reclassify the case as a murder motivated by antisemitism, a crime that carries a heavier penalty.

The judge, Anne Ihuellou, also ruled Mr Traore's mental state meant he should be protected from the French Jewish community's "hostile" attitude towards him.

But community leader Joel Mergui condemned the ruling, saying he could not understand it.

“It is definitely not good to be Jewish and to bear the name of Halimi in France,” he said, in a reference to the unrelated murder of Ilan Halimi in 2006.

“[They] were kidnapped, tortured and murdered because they were Jews. We thought the time of denial finally over. It seems that it is not so. I think I need to worry very legitimately.”