Police reinforcements were called to break up fights between groups of mainly Eritrean and Sudanese migrants that left 51 people hurt, one of whom was sent by helicopter to hospital with serious head injuries.
"The fights started after dinner and spread to the port area. They lasted most of the evening and into the night," local police authorities said.
One port worker estimated around 300 migrants were involved in running battles in the early hours of Tuesday.
This was the second consecutive night of scuffles between rival groups seeking passage to England. The previous night, 13 people were hurt in fights between around 150 people.
The number of migrants in Calais has grown "by some 50 percent in a few months", local authorities said.
Veronique Devise, from the Secours Catholique charity, said the situation had deteriorated and there was now "a bit of an explosive atmosphere".
"The migrants are so desperate. Sometimes they want to take a lorry by force and head off to England," she said.
According to official figures, nearly 7,500 illegal immigrants, mostly African, have been arrested since the beginning of the year as they attempt to reach Britain.
In May, French police expelled around 550 people from makeshift camps in Calais after a scabies outbreak, drawing criticism from rights groups.
This growing crisis has led to calls for France to change its policy towards migrants, with humanitarian groups claiming the policy of dismantling camps without providing alternative accomodation has failed miserably.
“We have to take into account the reality of the situation and this zone is a part of a circuit for people seeking asylum in Britain. It’s not going to stop tomorrow,” Jean-Claude Mas, secretary general of immigration support group La Cimade told The Local recently.
“Instead of discouraging people who have nothing to lose, and who are willing to do anything to make the crossing at Calais, why not get organized?”
Dr. Jean-François Corty, director for domestic programs at Doctors of the World (Medecins du monde) also told The Local: “We know that people will take all manner of risks and there will be more victims during the immigration process, but we can at least ensure the minimum standards for shelter and hygiene that you would find in a refugee camp, access to water and sanitation facilities."
“This would allow us the time to find solutions for the mid and long term.”