Cycling's governing body, the Union Cycliste Internationale, confirmed they were investigating the incident.
"Events on the UCI WorldTour calendar are of the highest level and require fully closed roads at all times. The UCI will consider lodging a complaint with the Disciplinary Commission against the event organiser RCS Sport.
Schachmann, who managed to get back on the bike and finish seventh, rued his bad luck.
"Unfortunately my collarbone is broken but in the end happy that it's "just" the collarbone," he said on Twitter.
"There are moments in life where you don't have your fortune in your own hands. I had one today..."
The race had earlier been stunned when pre-race favourite Remco Evenepoel flew over a bridge.
With 40 kilometres to go in the race, the 20-year-old was part of the leading group of riders, which included Kiwi George Bennett, when he misjudged a corner and went tumbling over a bridge and into the ravine below.
The images left fans stunned, with the drop to the ravine looking significant, and the race doctors rushing to the scene.
Fortunately, Evenepoel was conscious, and was immobilised as a precaution and taken to the hospital, with his team reporting that he had suffered a fractured pelvis.
Jakob Fuglsang went on to take victory, with Bennett finishing in second - the first New Zealander to claim a podium finish at a monument.
