Les Bleus have lost only one of their three RBS 6 Nations clashes so far but have been criticised for their lack of flair after new head coach Guy Noves adopted a more physical approach.
But Cotter is worried the French could punch a hole in his side’s fragile confidence following their first Championship win in two years when they meet at Murrayfield on Sunday.
To combat their robust game-plan, he has handed 16-stone Dunbar a return at centre following a year of injury frustration, while South African-born No.8 Strauss will add power to the pack after replacing Ryan Wilson.
Cotter said: “If you look at the French rugby culture, the first thing they talk about is physicality, winning their one-on-ones and dominating up front. We know that is what they have been talking about but we also know it’s coming. We need to get ready for it.
“Josh provides a different profile. He has a little more carry, a little bit more power and presence in the game.
“Alex offers something that perhaps we haven’t seen until now and a change-up may cause them a few headaches preparing for the game.”
Strauss, though, insists Scotland cannot worry too much about what France are planning as they look to build on the 36-20 win over Italy in Rome a fortnight ago.
“We have to stick to our strengths. We’ve got a game plan that has been building since the first game. It was just a little bit off in our first two games but worked against Italy and now we want to build on that this weekend.”
S Hogg (Glasgow); T Seymour (Glasgow), D Taylor (Saracens), A Dunbar (Glasgow), T Visser (Harlequins); F Russell (Glasgow), G Laidlaw (Gloucester, capt); A Dickinson (Edinburgh), R Ford (Edinburgh), W Nel (Edinburgh), R Gray (Castres), J Gray (Glasgow), J Barclay (Scarlets), J Hardie (Edinburgh), J Strauss (Glasgow).
S Spedding (Clermont Auvergne); W Fofana (Clermont Auvergne), M Mermoz (Toulon), G Fickou (Toulouse), V Vakatawa (French Rugby Federation); F Trinh-Duc (Montpellier), M Machenaud (Racing 92); J Poirot (Bordeaux-Begles), G Guirado (Toulon, capt), R Slimani (Stade Francais), Y Maestri (Toulouse), A Flanquart (Stade Francais), W Lauret (Racing 92), Y Camara (Toulouse), D Chouly (Clermont Auvergne).