Lille Trombone Festival 2019

[MJL]

Hello,
Does anyone know much about the Lille Trombone Festival, which is next scheduled for April 2019? I've never been to one of these before. Having looked at the website with my schoolboy French, it appears that these events seem to involve participants taking part in group playing - small ensembles and some very large ones - during mornings and afternoons, with an evening concert (usually featuring some very eminent players) to round off each day. Is this impression correct? (The Association des Trombonistes Francais also runs a festival in the summer in which the emphasis seems to be slightly less on participation, and much more on recitals and concerts.)
MJL.