Chapter XVII is the epilogue of A Plague Tale: Innocence. During it, you will learn the fate of the siblings after defeating the Inquisition. This stage unlocks during the final credits.
Go forward. At some point, Hugo runs up to the stall where shooting competition is being held. Your task is to shoot six targets. There is no time limit, so you should not rush.
After that, follow the road and turn left. Get to the entrance to the festival. Talk to the guards near that entrance. You can't get in - you have to move on. At some point, you will reach a cart. The sequence ends here.