The long-awaited inquiry threatens to implicate dozens of businesses, local and provincial governments, political parties, and even explore links to organized crime.
Given the size of the companies at the heart of the inquiry, its findings could also reach well beyond Quebec's borders.
One of the central figures in the controversies that have beset the province in recent years is Tony Accurso, whose network of construction companies have dominated the public-contract market in and around Montreal.
Accurso was arrested last month on fraud and conspiracy charges relating to an alleged kickback scheme in a Montreal suburb.
His business empire has a heavy presence in Ontario and Alberta. Louisbourg Pipelines, a division of Simard-Beaudry Construction Inc., was responsible for building a section of TransCanada's North Central Corridor pipeline in 2008.
Construction liens taken out in Ontario indicate that another Accurso affiliate, Banister Pipeline, laid down hundreds of natural gas pipeline for Union Gas Limited in municipalities across the province.
Accurso's companies have also been involved in a number of federal projects. A Canadian Press report revealed that they received millions from Ottawa's economic stimulus program for water infrastructure work in Quebec.
The inquiry's specific mandate is to examine the awarding of public contracts to the construction industry over the past 15 years.
But taken together with the media reports and criminal cases that have surfaced recently, the inquiry could paint an expansive picture of corruption.
Former Montreal police chief Jacques Duchesneau, who produced a report for the province's anti-collusion task force, even warned of disturbing links between organized crime groups like the Mafia and the worlds of politics and construction.
A recurring theme in recent allegations has been that elected officials benefited from kickbacks.
These has led to questions about the financing of Quebec's political parties.
Quebec's elections monitor found in 2010 that engineering firm Axor made a series of illegal donations to the Quebec Liberals by using numerous employees to circumvent laws preventing corporations from contributing to political parties.
To a lesser extent both the Parti Quebecois and the now-defunct Action democratique du Quebec also benefited from similar illegal donations.
It is these kinds of revelations that have prompted speculation that no one in Quebec's political class is safe.
"If there's enough of a big splash, everyone will get wet," said Pierre Martin, political science professor at Universite de Montreal.
"That's not good news because you would have then a general climate of suspicion for all the political system."
Even federal political parties may come under scrutiny. The governing Conservatives have also received many donations from players in the engineering firms implicated in construction-related controversies.
All these elements have Quebec journalists salivating at the prospect of a public inquiry that would rival, and perhaps even eclipse, Justice John Gomery's probe into the federal sponsorship scandal.
So far more than 160 journalists have signed up to cover the hearings, which get underway on Tuesday with a speech by the presiding judge, France Charbonneau.
Building on the unprecedented interest in the Gomery commission, the construction inquiry will stream its proceedings live and post all documents on its website.
"It will all be on the Internet in real-time," said the Charbonneau commission's spokesperson, Richard Bourdon.
"And presently there are negotiations with television networks to broadcast the proceedings live."
Quebec Premier Jean Charest spent two years resisting demands for an inquiry. He had said police probes and new, tougher laws were sufficient to deal with mounting evidence that the cost of public works was being driven up by criminal collusion involving organized crime.
He finally relented last year as public concern showed no sign of abating. Charest's government even recently agreed to expand the inquiry's power, giving it the ability to obtain search warrants.
But now with Quebecers finally getting what they demanded all along — a public inquiry with teeth — there is a concern the inquiry could do real damage to Quebec's democratic institutions, which are already reeling from a three-month student strike.
"No one is looking at this as a fun period — both on the government or the opposition side — it's too unpredictable," Martin said.
"None of the parties really benefit from the kinds of erosion in the public trust that will be directed at the whole political class."
The commission will sit four days a week, three weeks per month. Witnesses will be announced one to two days before they testify.
Charbonneau will begin hearing witnesses in early June for three weeks before picking up again in mid-September.
The commission must report by October 2013, right about the time Charest must call a provincial election.
There had been speculation Charest might hit the hustings before the inquiry.
But with his party still struggling in the polls, and student unrest in Quebec, the premier has held off on an election call.Suggest a correction