Investigators in Rome and Italy's highest administrative court looking into a unions claim that rules were broken during the bidding process for work on the 2,000 year-old amphitheatre.
The investigation is in early stages and according to news reports no evidence of a crime has surfaced.
Luxury Italian shoe company Tod's headed by owner Diego Della Valle is flipping the 25 million-euro bill to pay for the facelift that will include 5 million euros worth of scrubbing away the facade blackened by smog. In return for the funds. Tod's secured advertising rights at the Colosseum which attracts millions of visitors every year.
Uil together with consumer groups have also complained about the deal securing 15 years of exclusivity for Tod's to use the Italy's most familiar landmark for advertising. to complicate matters, an artisans trade group called for all work to be halted because it was set to be carried out by construction workers, rather than skilled restorers.
The work, expected to last two years, was slated to start in March. It is not clear if there will be a delay.
The need to restore Italy's the Colosseum made headlines first in May when pieces of mortar and lime fell from the walls. More recently, pieces of tufa rock broke off the monument on Christmas and on 27 December raising concern about the urgency for repairs.