According to https://www.discogs.com/release/3412721 the US release does not have a barcode either. Note the "Complete Recording/Gesamtaufnahme" on the cover, which might be a hint that there's just one international release. (It doesn't matter if 018111590020 is a valid barcode; what matters is what's printed on the actual item.)
EDIT: Or is the Discogs release the DE release? Hm.