Germany and France will push European Union finance ministers June 14 to rally around a financial transaction tax that could help fill a potential EU Brexit budget hole.

Ten EU countries have provisionally agreed to adopt a minimum 0.2% levy on equity trades of companies based in the EU that have a market capitalization value of 1 billion euros ($1.12 billion). The pending accord was forged after more than five years of negotiations using a special legislative procedure designed to circumvent EU unanimity rules when it comes to tax legislation.

“The revenue should flow into the EU...