Race commissaires confirmed the ruling after the race, listing him in the official results sheet as a DQ.
The incident was picked up by the Tour's new video commissaire.
Team Sky is less than impressed with the Italian.
“We support and accept the decision by the race organisers to exclude Gianni Moscon from the Tour de France," Team Sky principal Dave Brailsford said in a team statement.
"Gianni is desperately disappointed in his behaviour and knows that he has let himself, the team and the race down. We will address this incident with Gianni once the Tour is complete and decide then if any further action should be taken.
"I would like to offer my sincere apologies to both Elie Gesbert and Team Fortuneo Samsic for this unacceptable incident. Team Sky will be making no further comment at this time."
The rider too has publicly apologised.
It's not the first such incident involving the troubled Italian. In June, the UCI cleared him of allegedly causing a crash which resulted in Groupama FDJ's Sébastien Reichenbach fracturing an elbow at a race in October 2017.
Sky suspended the rider for six weeks in May 2017 following a racist slur hurled at Groupama FDJ's Kevin Reza which resulted in a fight after a stage at the Tour de Romandie.
At that time, the team said in an "Gianni knows that there is no excuse for his behaviour and that any repeat will result in termination of his contract."
He also was disqualified from his 29th place at the 2017 road world championships in Bergen after he was caught by a moto camera taking a tow from his team's car after crashing in the final 35 kilometres.
