Three others suffered "multiple injuries". A fifth is also in "very serious condition" and was transported to the hospital in Lille, the authorities added, without disclosing the age and nationality of the injured.
Mr Macron also travelled to the United Kingdom where Prime Minister Theresa May agreed to pay more to help stop migrants reaching the United Kingdom, and to take in more minors who are without their family.
However, as recently as November 2017, gunshots were fired during a fight between two groups of Afghan migrants, with five seriously injured. Scuffles broke out after Afghan migrant came to receive food handouts and were confronted by a crowd of African migrants, according to a prosecutor.
"I will meet our security forces and emergency services in particularly hard times".
More than 100 illegal immigrants and 50 law enforcement were involved in that violent scuffle, which erupted after migrants tried to stop police from dismantling their newly-built camp and destroying their tents. At least 12 people were injured there by "blows from iron bars", news agencies report.
Migrants have long arrived in the port city in hopes of reaching Britain, a mere 20 miles across the English Channel.
Calais was home to the unofficial "jungle" refugee camp, which housed thousands of refugees in tents, until French authorities demolished it in October 2016.
Charities said they had been warning the authorities of the risky and violent potential of smuggling criminal gangs in Calais, and the "destructive" influence they hold over those in the region.
Last month, during French president Emmanuel Macron's visit to the UK, Britain agreed to the signing of a new treaty created to improve security in Calais.
The new pact will cover unaccompanied children and will reduce the processing times for cases from six months to one month for adults, and from six months to 25 days for minors.