MONTREAL—On Monday, a witness at the Charbonneau Commission took direct aim at former Mayor Gerald Tremblay, linking him to one of the most infamous contracts of his time at city hall.

Claude Leger was general manager of the City of Montreal from 2006 until 2009. During that time he presided over the failed water meter contract. Leger told Justice Charbonneau on Monday that he warned the city the $350-million project was too ambitious.

According to Leger, pressure to push the project through quickly came from the very top: Tremblay’s office and that of his main lieutenant, Frank Zampino.

Upon arriving at city hall, Leger told the corruption inquiry that he quickly learned that then executive committee chair Zampino held the real power over projects and management in Montreal.

He testified that city managers could not criticize the administration or they would be forced to resign. His proof: Montreal went through six managers in 15 years.

“We felt a lot of pressure, it was too fast; we didn't have time to study things fully,” said Leger.

That came on top of pressure to steer contracts to friends of Union Montreal, the mayor’s political party, according to Leger.

“Someone was doing a sales pitch for this, someone who convinced the mayor it was important,” the witness continued.

Who was doing the sales pitch?

“I can't prove it, but I'm inclined to think it was Mr. Zampino,” Leger answered.

Suddenly, Zampino left city hall to work for the engineering firm responsible for the water meters, leaving leger responsible for a project he never believed in. When an emerging scandal about the cost of the meters threatened to derail Mayor Tremblay's 2009 campaign, Leger agreed to become the fall guy.

“Executive members were telling me, politics; is cruel, but that I went beyond the call of duty.”

So why didn't Leger sound the alarm? He admits he was worried for his job.

“I’m sorry,” he said, taking a long pause.

The commission is not done dealing with city hall. The next three witnesses will all talk about how Union Montreal raised funds for Tremblay's reelection campaigns.

Union Montreal organiser Christian Ouellet testified late on Monday that no illegal money was ever collected, an allegation contradicted by at least 10 witnesses so far.