A global deal on corporate tax looks set to bring to a climax a deep-seated European Union battle, pitting large members such as Germany, France and Italy against Ireland, Luxembourg and the Netherlands.

The smaller EU partners, which are at the center of a yearslong struggle over their favorable tax regimes, welcomed a Group of Seven deal on June 5 for a minimum corporate rate of at least 15%, but some critics predict trouble implementing it.

The European Commission, the EU's executive, has long struggled to get agreement within the bloc on a common approach to taxation — a freedom that has been jealously guarded by all its 27 members, both large and small.