France will hold a referendum on the European Union constitution on 29 May, the president's office has announced.
French President Jacques Chirac helped push Spain's Yes campaign
President Jacques Chirac has been a keen supporter of the treaty, which must be ratified by all 25 EU members.
Earlier this week the French parliament adopted an amendment to the country's constitution, to allow for the EU poll.
Spain became the first country to back the treaty through a referendum on 20 February while some countries have approved it with parliamentary votes.
The BBC's Caroline Wyatt says Mr Chirac is keen to hold this referendum as soon as possible, to capitalise on the momentum of the Yes vote in Spain.
He also wants to avoid the constitution being used as a chance for the French to deliver a protest vote against his government's unpopular economic reforms.
While current opinion polls suggest 63% of the French will vote Yes, many people remember that the last referendum - on the Maastricht Treaty - passed with a majority of just two percentage points in 1992.
Our correspondent says that the opponents of the constitution, who also kick off their campaign next week, are a more disparate group, ranging from Socialists who say Europe is becoming too economically liberal to centre-right MPs who fear that France will lose its ability to determine its own future and has already ceded too many powers to Brussels.