About 100 Eritreans and 30 Afghans started fighting in a charity food queue.
Later, up to 200 Eritreans armed with iron rods and sticks clashed with about 20 Afghans At least three migrants were taken to an emergency ward in Lille for immediate surgery.
The rest of those with gunshot wounds, and others with injuries caused by clubs and knifes, were taken to the hospital in Calais.
It remains unclear who had carried out the shooting.
Confrontations occur regularly between groups of different nationalities in Calais, but tensions have spiralled in recent weeks.
In November, five were shot in a fight between rival Afghan groups.
The French need to get these migrants out of Calais and help them back to their home nations – and arrest the ruthless people traffickers causing such mayhem and misery.’ The violence comes two weeks after President Emmanuel Macron visited Calais with a message of zero tolerance on migrants setting up camps like the Jungle.
Four Eritrean teenagers, who were shot in the neck, chest, abdomen and spine, were in a critical condition.
The true number who reached the continent could be even higher.
‘The serious incidents multiplied from this afternoon,’ she said.
The United Nations has estimated as many as 5,000 are fleeing the country every month.
They are escaping the repressive regime of President Isaias Afwerki, a freedom fighter turned dictator who was described as ‘cruel and defiant’ in leaked US diplomatic cables.