The French railway company SNCF has complained that many riders in the Paris-Roubaix race ignored a level crossing barrier.
Riders went over the tracks when a high-speed train was approaching, which was described as irresponsible by the company.
“Several riders deliberately crossed a level crossing, which is against all safety regulations. Millions of TV viewers were able to watch this unauthorised crossing which was extremely serious and irresponsible, that could have ended in tragedy.
“SNCF has decided to lodge a legal complaint and will leave it up to the investigation to determine who was responsible and we regret that such foolhardiness took place.”
Sir Bradley Wiggins failed to sign off from Team Sky with a win at Paris-Roubaix as Germany's John Degenkolb triumphed in the gruelling 151-mile trek.
The 2012 Tour de France champion, who is quitting both Team Sky and the road in order to return to the track ahead of the Rio Olympics, was in contention for victory but faded near the finish to come home 18th.
Earlier in the race, several riders came close to being hit by a train as they raced over a rail crossing as a TGV approached.
Norwegian Alexander Kristoff won cycling's Tour of Flanders on Sunday, holding off Dutchman Niki Terpstra in a sprint finish.
Britain's Geraint Thomas, one of the pre-race favourites, had to settle for finishing 14th.
The Welshman had hoped to become only the second Briton ever to win the Belgian race, where Tommy Simpson was victorious in 1961.
The International Cycling Union and Astana Pro Team have dismissed a report that the team of 2014 Tour de France winner Vincenzo Nibali have been stripped of their WorldTour licence by the Independent Licence Commission.
Last month the UCI requested that Astana's licence be revoked by the commission following an independent audit into their procedures, which came after a number of anti-doping infringements by Astana and their feeder team.
On Monday, Dutch newspaper De Telegraaf reported that Astana would lose their WorldTour licence and would only be allowed to apply for a Continental licence, the third tier of professional cycling, saying the decision had been made on March 20.
However, the UCI said the case had not yet been heard.
"Following a misleading article published today in Dutch newspaper De Telegraaf, the Union Cycliste Internationale (UCI) would like to clarify that no hearing has yet taken place in the Astana case and therefore no decision has been made," a UCI statement said.
Tinkoff-Saxo has announced that team manager Bjarne Riis has been suspended, but denied the move was because of a lack of results.
Riis is one of the subjects of an investigation into past doping practices in his native Denmark, having belatedly admitted to using performance-enhancing drugs during a career which included victory in the 1996 Tour de France.
Rumours surfaced on Sunday that Riis had been suspended due to poor results by Tinkoff-Saxo owner Oleg Tinkov.
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Cycling boss Brian Cookson says Lance Armstrongis being 'completely disrespectful' by riding Tour de France route for charity.
Cookson, president of the Union Cycliste Internationale (UCI), suggested Armstrong 'would be well-advised not to take part' in former Crewe Alexandra and England footballer Geoff Thomas' charity fundraising plan.
"I'm sure that Geoff Thomas means well, but frankly I think that's completely inappropriate and disrespectful to the Tour, disrespectful to the current riders, and disrespectful to the UCI and the anti-doping community," Cookson said at the Sport Industry Breakfast Club.
"I think Lance would be well-advised not to take part in that."
Team Sky rider Richie Porte reeled in a 36-second gap to win the Paris-Nice title for the second time in three years.
The Australian was well placed but still significantly behind Tony Gallopin heading into the final day, but while Porte surged the overnight leader fell away on the Col d'Eze time-trial.
Porte said: "It means a lot to me to be a two-time winner of an iconic race like Paris-Nice, and this one feels even sweeter than the last one because it was so hard. They threw everything at us yesterday, and to win on the top of the Col d'Eze this year, like I did in 2013, is incredible."
Twice Tour de France champion Alberto Contador has signed a new one-year contract that will keep him at the Tinkoff-Saxo team until the end of next season.
"Tinkoff-Saxo is delighted to announce the Spanish six-times Grand Tour winner will remain as its leader until the end of the 2016 season," the Russian-owned team said in a statement on Tuesday.
"Alberto Contador is undoubtedly one of the world's best stage racers and a legend in his lifetime."
Last month the Spanish cyclist indicated that next season could be his last as a professional.
Frenchman Lloyd Mondory has failed an out-of-competition test for the banned blood-booster EPO, the International Cycling Union (UCI) confirmed on Tuesday.
"The Union Cycliste Internationale (UCI) announces that it has notified French rider Lloyd Mondory of an Adverse Analytical Finding of EPO in a sample collected in the scope of an out-of-competition control on 17 February 2015," the UCI said in a statement.
"In accordance with the UCI Anti-doping Rules, the rider has been provisionally suspended until the adjudication of the affair."
The AG2r-La Mondiale rider has the right to request that his B sample be tested.