Officials noted Charles Leclerc as the Monaco Grand Prix winner joined the track at the start of the second practice hour in Montreal.

The mixed conditions which had dominated the opening practice session had remained as Free Practice 2 began.

A queue of cars formed at pit exit to get on track while it was still, mostly, dry before expected rain doused the resurfaced venue once again.

Leclerc was not among those who queued up, joining the session half a lap later.

He did so after team-mate Carlos Sainz, who was the fourth car on track, reported that conditions were too slippery for slick tyres.

In response, Ferrari sent Leclerc out on a set of intermediate tyres. However, the session was only declared wet five minutes in.

Teams are not allowed to fit wet or intermediate rubber unless conditions have been declared as such.

That point did not escape officials who first noted the incident before investigating it post-session.

The outcome was a €5000 (AUD $8200) fine for the team.

“Car 16 left the pit lane on intermediate tyres at the beginning of the session despite the fact that the track had not been declared wet and returned to the pits after one lap,” stewards noted.

“This constitutes a breach of Art 30.5 l) which only permits the use of intermediate or wet weather tyres after the track has been declared wet by the race director.”

Leclerc was fourth fastest at the end of the session, banking a lap just before the midway point of the practice hour when conditions were at their best.

“There was not so much to learn today, as the conditions were very different each time we went out,” he noted.

“We put in quite a few laps throughout the day, so that was a positive.

“I’m looking forward to tomorrow and we will try to put everything together for qualifying.”