There are a bunch of reasons why I like Jean simply from a character design standpoint, but in addition to him hitting multiple buttons for me at once he’s also just interesting because of his significance in-game. Even with the few times he appears and interacts with Harry and others, there’s still so much dense info doled out from him- not just about Harry’s past, but also Jean himself and their relationship.
One of the very base readings of Jean is that he’s simply an asshole. And, like, yeah he is (that’s what’s so fun about him, haha). But that impression also becomes heightened by Harry’s lack of knowledge about why Jean is mad at him. Or who Jean even is to him.
So, from the player’s perspective, we also lack that knowledge and have to come to our own conclusions about Jean’s character and who he is to Harry through reading between the lines and picking up the clues the game sprinkles into their interactions and what few memories of Harry’s past we get.
What the game ends up showing us are a couple of important things: Regardless of how Harry is played, his past self was a drunk, an addict, erratic and violent. It may only have gotten really bad in the year leading up to the case in Martinaise, but this is alluded to by Harry’s emerging memories, his ledger and fellow police officers. It’s an undeniable fact that past!Harry had become an awful person.
Jean is mad at Harry and doesn’t believe he’s lost his memory, because as his partner- and likely the closest person in Harry’s life by the time right before the game begins- he’s watched Harry’s self destruction and tried to help him as well as picked up after him for all this time.
This is not the anger of someone who hates Harry. It’s the anger of someone who deeply cares for him and who has been let down over and over again, both on a personal and professional level.
I see this especially in the ways Jean repeatedly claims that Harry is drunk, no matter whether Harry has stayed sober in Martinaise or not. He’s seen the attempts at sobriety before and has clearly been disappointed too many times to believe it’s going to last.
Another important aspect is that despite Harry’s seeming inability to understand why Jean is so mad at him, both Jean and the game’s text itself pretty much lay it out for us: Harry told Jean (and everyone else from C-wing) to fuck off. As the highest ranking officer on the case and as the leader of the team and Jean’s partner, he essentially took everyone else off the case. Harry was the one to push everyone away.
The implied part are the hurt feelings.
When Jean returns to Martinaise, it’s not with the expectation that Harry has lost his memory. He returns, because he was worried and in a disguise he expected Harry to see through and find funny. A peace offering. A way to make Harry laugh and pick things up where they left off.
Instead, Jean gets ignored. Considering the falling out they had a few days ago, his first assumption wouldn’t be that Harry has lost his memory, but that Harry is ignoring him deliberately. He’s reluctant to believe Harry’s explanation of having amnesia, because honestly, it sounds too convenient. Like a mean prank Harry is playing on them, to punish them for turning up again.
Just because Judit starts to believe Harry doesn’t mean Jean is willing or able to allow himself to believe him. It sounds ridiculous, for once. Again, a cruel joke in his head is the more probable answer. But also, and this is the part that’s implied again: It’s painful.
If he accepts the fact that Harry has lost his memory, he’ll also have to come to terms with the fact that the person in front of him doesn’t remember him. His partner, his friend, the person Jean cared about and who, despite all his failures, probably still cared about Jean, is gone.
Getting angry at the version of Harry that now only exists in Jean’s head is easier. It’s less painful than being forgotten.