AFP journalists said at least nine Iranians had stitched their mouths shut in the southern half of the camp, which is being gradually demolished by French authorities.
One carried a sign, saying “Will you listen now?”
In a statement, Calais town hall said the unsettling protest had aroused “deep emotion”.
“But at the same time, nothing justifies such extremes when the state has done everything to take the migrants out of these undignified conditions,” it said.
Thursday's protest followed a similar act by a group of Iranian migrants on Wednesday (see photos below).
They took a needle and thread and sewed their lips together before brandishing signs and banners that read: “We are humans” and “Where is our democracy? Where is our freedom?”
Another banner read: “I left my country and I came here to find my human rights but unfortunately I found none.”
The men had just witnessed French workers pull down their makeshift huts as part of a plan to clear hundreds of migrants out of part of the “Jungle” camp.
On Wednesday charred husks of shacks and smouldering logs marked the spots where half a dozen shelters were burned down overnight in the camp on the outskirts of the northern French port city.
The blackened shells sat alongside the now-empty stretch of land that has already been cleared in the southern half of the camp, the authorities' initial zone of operations.
France has offered the evicted migrants places in heated containers next to the Jungle, or in one of 100 accommodation centres around the country.
But many are reluctant to give up their dream of smuggling themselves across the Channel to England, where they have family or community ties, or see greater hope of finding work and education.
French authorities began demolishing the southern half of the camp on Monday, and by Thursday they were still razing makeshift shelters under heavy police protection, drawing ever closer to one of the main food distribution
centres, which serves around 1,000 meals a day.