Paris -Tour de France organisers inadvertently published next year's route on their official website, according to several specialist cycling websites on Monday.
Amaury Sport Organisation (ASO) refused to comment when contacted by AFP about the embarrassing slip-up over the race which gets underway in the Belgian town of Liege on June 30.
The page is no longer accessible but Dutch journalist Stephan van der Zwan has some images he took of it on www.Wielerland.nl, the website that revealed the error.
The 2012 Tour will feature nine flat stages, five mountain stages including two finishing at altitude, two individual time-trials and a prologue. There will also be two rest days.
The race will comprise a total of 25 climbs of 2nd, 1st or Hors category: one in the Vosges, three in the Jura, four in the Swiss Jura, six in the Alps and 11 in the Pyrenees.
The official unveiling of the route is due to take place in Paris on October 18.