The agreement, based on interim talks in December, outlines the conditions for Britain's exit from the bloc.
However, a particular focus of the draft – which caused trouble in Belfast – concerns the protocol on a so-called "hard border" between the Republic of Ireland and Northern Ireland.
Barnier said that after Brexit, Northern Ireland would have to stay within the current EU rules. He also underlined that this "backstop" agreement with British Prime Minister Theresa May was reached late last year.
Northern Ireland's Coalition Partner, the Democratic Unionist Party (DUP), has long criticized this protocol. The DUP threatened to withdraw its support for questioning Westminster's physical infrastructure at the Irish border.
The legally binding text comes just days before May to hold its long-awaited speech on Brexit since last year.