A tie-up between advertising mega firms Omnicom (the world's second biggest agency) and Publicis (the third) has been granted approval by EU antitrust regulators.
When the deal was announced in July, the combined market capitalisation of the two stood at $35.1bn (£21.3bn).
"The merged entity would be sufficiently constrained by several competitors, including large international advertising groups," the European Commission said in a statement.
"Should the merged entity increase its prices or decrease the quality of its services, customers would have the ability to switch."
Omnicom will keep its headquarters on Madison Avenue, at the heart of New York’s advertising business, while Publicis will retain a base in Paris. The firms employ a total of 130,000 people.