The incident, first reported in local newspaper La Nuova di Venezia, took place near the Bareteri bridge in the heart of the historic centre, where a group of four apparently climbed aboard a stationary gondola to take pictures.
The gondolier told them to disembark and a fight ensued, according to La Nuova, which says that the gondolier was knocked to the ground by a punch from one of the tourists.
A video filmed by onlookers and shared on Facebook shows a man jostling and threatening a gondolier, knocking off his traditional straw hat before head-butting him and hitting his face. In the minute-and-a-half clip, the gondolier argues with the man but does not hit him back.
Other gondoliers have experienced trouble with rowdy tourists, according to La Nuova, which says a similar argument broke out near the same bridge last year.
Some visitors have capsized gondolas by standing up during a ride, while more than one person has faced charges for taking the wooden boats on late-night joy rides.
In one 2017 video that went viral, a gondolier captured a group of tourists more occupied with their phones than the scenery around them, commenting sarcastically: "A fantastic ride. The customers are very happy, they're enjoying the beauty of the city, they appreciate it a lot."
The relationship between Venice and its visitors is often strained, with the city's economy dependent on tourism but its residents increasingly frustrated with the crowding and disruption that comes of hosting 12 million tourists per year.
Authorities have introduced swathes of ordinances to regulate public behaviour, cracking down on everything from snacking in public to wheeling trolley suitcases to failing to wear a shirt.
But many criticize the government for failing to regulate those profiting from mass tourism, especially the cruise ship companies that ferry thousands of people into the historic centre at once.
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