The South Africa-born back-row will make his first Six Nations start against the French, having become eligible to play for Scotland ahead of last year's World Cup.
"At this level, every game is a must-win game," said Strauss. "Pride-wise, though, this is a must-win game.
"It's very big for us. We feel everything is in place for us."
Strauss wants his team to build on the momentum generated by the victory over Italy in Rome last time out that ended the Scots' nine-match losing run in the Six Nations.
"We feel there has been a constant improvement in the team," he said. "That's a very important factor at this level, trying to build on the positives and trying to get the negatives out of the game.
"Two weeks ago against Italy, things came together nicely. We've got to build on what we did well."
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The form of David Denton resulted in Strauss playing a less prominent role in Scotland's World Cup campaign than many had anticipated, but now he wants to stake a claim for the number eight jersey in Vern Cotter's team.
"It's obviously a very big opportunity for myself," said Strauss, who replaces Glasgow Warriors team-mate Ryan Wilson in the starting XV.
"It's been a bit of a topsy-turvy experience with the World Cup and coming straight back into the Pro12. It's the first time I've experienced something like it.
"It was a very different experience and I struggled a bit with injuries before the Six Nations, which I think threw me off a little bit more.
"But I'm just happy to get back into the squad and get working."
Strauss is keen to make an impact after preparing with the squad for previous games.
"I've been in since the start, but I've been biding my time just training with team, trying to get my fitness back to where it has to be to play a game," he added.
"I've had a few games for the Warriors and I feel like my fitness is where it has to be.
"Everyone wants to start. Everyone wants that jersey."
Scotland forward Josh Strauss says pride dictates that Sunday's match against France is a "must-win game".