It's such a short chapter, but there are brief moments where you're given the opportunity to move around; exactly the sort of place unscrupulous treasure hiders would stick a couple of treasures.
Are there any treasures, or is the first treasure in the flashback in Chapter 2?
There are two treasures in the first chapter. One is in the bar game machine by the pub's main entrance and the other, as Alex mentioned is behind the bar. Both are available after the fight finishes in the bathroom.
I've only found one - behind the bar just before you leave into the kitchen with Sully, walk behind the bar instead of through the door. There's a treasure amongst the bottles there. From what I recall reading in the Chapters menu there is a second one somewhere, but I haven't found it (yet!).
