The bus driver was detained and put in police custody on Wednesday after the alleged accident. The driver is suspected of knocking over the biker and dragging him and his bike.
The bicyclist phoned the police and was taken to hospital with "several bleeding wounds", Le Parisien reports.
A police source says the alleged assault occured after the biker and the bus driver had an argument over using the bus lane. In Paris, buses, taxis and bikers are all allowed to use the same lane. The police source says the biker was dragged over "a hundred metres".
The Paris transport company RATP denies these allegations. A spokesperson told Le Parisien that the rider and the bus driver did argue but that the bicyclist hurt himself when he jumped off his bike. The bike was then dragged on the road for several metres.
Thursday afternoon, the bus driver was still in police custody.