I wondered, due to fact that Nice had been previously besieged.
The Siege of Nice occurred in 1543 and was part of the Italian War of 1542–46 in which Francis I and Suleiman the Magnificent collaborated in a Franco-Ottoman alliance against the Holy Roman Emperor Charles V, and Henry VIII of England. At that time, Nice was under the control of Charles III, Duke of Savoy, an ally of Charles V. This is part of the 1543–1544 Mediterranean campaign of Barbarossa.
Thus the wikipedian article Siege of Nice
In the bracket "Casualties and losses" no deaths are cited. But, on side of Genoa, 4 galleys, 5,000 captives.
The Ottoman force first landed at Villefranche, 6 kilometers east of Nice, which it took and destroyed.
The French and Ottoman forces then collaborated to attack the city of Nice on 6 August 1543. In this action 110 Ottoman galleys combined with 50 French ones.
The Franco-Ottomans were confronted by a stiff resistance which gave rise to the story of Catherine Ségurane, culminating with a major battle on 15 August, but the city surrendered on 22 August. The French prevented the Ottomans from sacking the city. They could not however take the castle, the "Château de Cimiez", apparently because the French were unable to supply sufficient gunpowder to their Ottoman allies.
A cannonball fired by the Turkish fleet, now at the corner of "Catherine Ségurane" street, or "Rue Droite", in Nice. A plaque reads: "Cannonball from the Turkish fleet in 1543 during the siege of Nice, where Catherine Ségurane, heroine of Nice, distinguished herself."
Another important battle against the castle took place on 8 September, but the force finally retreated upon learning that an Imperial army was on the move to meet them: Duke Charles III, ruler of the Duchy of Savoy, had raised an army in Piedmont to free the city.
The last night before leaving, Barbarossa plundered the city, burned parts of it, and took 5,000 captives. The relief army, transported on ships by Andrea Doria, landed at Villefranche, and successfully made its way to the Nice citadel.
During the campaign, Barbarossa is known to have complained about the state of the French ships and the inappropriateness of their equipment and stores. He famously said "Are you seamen to fill your casks with wine rather than powder?". He nevertheless displayed great reluctance to attack Andrea Doria when the latter was put in difficulty after landing the relief army, losing 4 galleys in a storm. It has been suggested that there was some tacit agreement between Barbarossa and Doria on this occasion.
So, the story as given here does not tell if very many were actually killed. 84 dead could be the worst massacre in its history./HGL