I think this is the first time that Golden snub-nosed monkey have been kept in captivity in European zoos.(Although there may already be zoos that have kept them in the past.)
@captain alligator ZTL lists London Zoo as having kept them in the late 1930's and Dublin as having had some temporarily on display in 1987, so it is not totally the first time in Europe, although it seems to be the first time on the European mainland. Although the arrival of golden snub-nosed monkeys (two different subspecies) at Beauval and Pairi Daiza is the first time this species can be seen in Europe in decades, and likely within the memory of many zoo fans.
@KevinB However, isn't this the first time in 38 years that golden snub-nosed monkeys have been kept in a European zoo (until then they had only been kept in East Asian zoos)?