On 5th July, CMS Law published a set of guides which provide a summary of basic information on each jurisdiction saying what forms of gambling are licensable, and provide answers to – can online operators licensed in other EU Member States offer their online services?; and can online operators licensed in other EU Member States advertise their online services?
https://cms.law/en/INT/Expert-Guides/CMS-Expert-Guide-to-Online-Gambling-Regulation-in-Europe