Again, really hard to say with confidence if this is sprint or breakaway.
One might think this is 90% likely to be a sprint but "flat" stages late in Grand Tours (after mountains) often get weird. This is possibly even more the case at the Tour when there is still the Champs Elysee to think about, which carries more prestige than this.
Looking at penultimate Tour "flat" stages in the last ten years, when they come after mountains (small sample size, I know):
2021 - Stage 19 - Breakaway wins (Mohoric)
2020 - Stage 19 - Late attack wins (SK Andersen)
2019 - N/A - Champs Elysee the only flat stage after mountains
2018 - N/A - Champs Elysee the only flat stage after mountains
2017 - Stage 19 - Breakaway wins (EBH)
2016 - N/A - Champs Elysee the only flat stage after mountains
2015 - N/A - Champs Elysee the only flat stage after mountains
2014 - Stage 19 - Late attack wins (Navardauskas)
2013 - N/A - Champs Elysee the only flat stage after mountains
2012 - Stage 18 - Cavendish wins bunch sprint
I think today's stage is still probably a sprint, because at least five teams will think they have a worthwhile chance in a sprint, but everyone is very tired. And it'll be very hot. If, say, three of those five interested sprint teams get a man in the breakaway then it won't be coming back.
So, anyway, for me:
Philipsen (3-1) in case it's a sprint. I think he's the fastest right now, plus the slight uphill finish suits him, plus he appears to have coped better in the mountains than the other sprinters (hasn't finished in the last group on any of the last three stages).
DeWulf (275-1) from the breakaway. I think this guy has really good legs. He looked super powerful getting into the early breakaway yesterday, even though it didn't stick. He's generally good at making breaks (got into 3 in the last 5 stages of last year's Vuelta) can win solo and has a decent sprint if it comes down to a small group. He's a total longshot, obviously, but I think he's paying at least double what he should be.