Ferrari say they expect to struggle compared to Mercedes at this weekend's French Grand Prix.
Sebastian Vettel won on track at the last race in Canada before being stripped of the victory because of a penalty for dangerous driving.
Ferrari team boss Mattia Binotto said the French track will not suit the car.
"Paul Ricard was a tricky circuit for us last year and we know this kind of track isn't particularly favourable for our package," Binotto said.
However, Mercedes F1 boss Toto Wolff said Ferrari's straight-line speed advantage could again pay dividends for the Italian team.
"We expect another tough fight in France," Wolff said. "The circuit features some similarities to Montreal and the long straights will present a challenge for us.
"However, unlike Canada, the corner characteristics are spread across a range of speeds, which should play to our advantage. We're looking forward to the chance to put a few things right again."
Mercedes' Lewis Hamilton dominated in France last year, after Vettel collided with the Briton's team-mate Valtteri Bottas at the first corner.
The other Ferrari driver Kimi Raikkonen, who has been replaced for this season by Charles Leclerc, was beaten to second place by Red Bull's Max Verstappen.
In overall terms, Ferrari have been less competitive this year - Vettel went into the French race last season with a one-point lead in the championship over Hamilton.
This year, Hamilton is 62 points clear of Vettel, and 29 ahead of Bottas, after seven straight wins for Mercedes, five of them for the world champion.
Ferrari's car has lacked downforce, which has led to slow cornering speeds and a general lack of competitiveness compared to Mercedes, and Binotto said the team had some developments on the car this weekend that he hoped might point them towards a solution.
"We will have a few small evolutions, elements that represent for us a useful step in defining the direction we will take in developing the car," Binotto said.
"What we will be bringing won't be the solution to our problems, but the technical feedback we get from these evolutions will be important for the next steps we take."
German Vettel sounded more optimistic than Binotto, saying: "I think our car can have the pace to do quite well there."