The 32-year-old has now drawn a blank in his last 11 Formula One races, extending back into 2017, and is one of only two drivers yet to open his account this season.
In Spain he spun at the start, taking out two other cars in an incident that left him with a three place grid penalty for Monaco.
In Azerbaijan before that, the Frenchman spun into a wall while the safety car was deployed in an embarrassing accident that he blamed on mistakenly flicking a switch.
"His competitiveness in Canada was good," Steiner told reporters.
"I think he got his confidence back after what happened in Barcelona and Baku. I think he’s in good spirits after Canada. He’s very positive about the upgrade we brought to Canada, which we have here.
"He was very happy with the car, very comfortable with it, just the result wasn’t there."
Grosjean finished 12th in Canada after starting last because he had failed to set a time in qualifying due to an engine problem.
He climbed as high as seventh and did 48 laps on one set of tyres in the hope of a safety car period, that never came, lending a hand.
Sunday's race is the first French Grand Prix in a decade and first at Le Castellet, near Marseille, since 1990.
Steiner said the engine that expired in a cloud of smoke at the start of Canadian qualifying had been inspected by Ferrari and given the all-clear.
"No damage to the turbo. It was ... oil which leaked into the cylinder and therefore the smoke came out but no damage," he said.
Steiner recognised that Haas, the only U.S.-owned team in Formula One and currently eighth out of the 10, had so far under-performed on the track.
"We shouldn’t be where we are, we’re fully conscious of this. The car is competitive so we have no excuse on that side," he said.
"We just need to get a race weekend with both cars in the points and we can make up points pretty quick if everything goes right. But nothing seems to be going right at the moment."
Steiner said there would be no decisions about the drivers until after the August break.
(Reporting by Alan Baldwin; Editing by Alison Williams)
