Ordered as part of the second tranche of the 1900 naval law that authorized a total of 19 battleships by 1919, Mirabeau was named after Honoré Riqueti, comte de Mirabeau, an early leader of the French Revolution.
Construction of the ship began on 8 May 1906 at the Arsenal de Lorient and she was laid down on 4 May 1908.
Mirabeau was launched on 28 October 1909 and was completed (armement définitif) on 1 August 1911.
Upon reaching Toulon on 15 August, the ship became the flagship of Rear Admiral (Contre amiral) Dominique-Marie Gauchet, commander of the Mediterranean Squadron (Escadre de la Méditerranée's) Second Division (2ᵉ Division de cuirasée) of the First Battle Squadron (1ʳᵉ Escadre de ligne).
Together with four of her sisters, she participated in a large naval review by the President of France, Armand Fallières, off Cap Brun on 4 September and then the visit by the Navy Minister, Théophile Delcassé on the 8th.

In mid-April 1912, the First Battle Squadron hosted three British armored cruisers at Golfe-Juan as their commander, Rear-Admiral Edward Gamble unveiled monuments to King Edward VII and his mother, Queen Victoria, at Cannes.
Mirabeau participated in the July maneuvers in the Western Mediterranean and the exercise simulating a blockade of Ajaccio, Corsica, in November.
On 3 March 1913 the First Battle Squadron conducted gunnery training off the Îles d'Hyères with the First Lord of the Admiralty, Winston Churchill, observing.
The ship participated in combined fleet maneuvers between Provence and French Tunisia in May–June and the subsequent naval review conducted by the President of the Council, Raymond Poincaré, on 7 June.
Rear Admiral Marie-Jean-Lucien Lacaze relieved Gauchet on 16 August and Mirabeau joined her squadron in its tour of the Eastern Mediterranean in October–December, making port visits in Egypt, Syria, and Greece.

Lacaze shifted his flag to her sister Voltaire on 12 March 1914 and the ship had to briefly withdraw from the grand fleet exercises on 13 May due to engine troubles.
As tensions rose during the July Crisis, Mirabeau and the other ships of the First Battle Squadron downloaded their practice ammunition and exchanged suspect lots of propellant for new ones beginning on 27 July.
They recoaled four days later and the Marine Nationale mobilized on 2 August.
Ordered as part of the second tranche of the 1900 naval law that authorized a total of 19 battleships by 1919, Mirabeau was named after Honoré Riqueti, comte de Mirabeau, an early leader of the French Revolution. Construction of the ship began on 8 May 1906 at the Arsenal de Lorient and she was laid down on 4 May 1908. Mirabeau was launched on 28 October 1909 and was completed (armement définitif) on 1 August 1911. Upon reaching Toulon on 15 August, the ship became the flagship of Rear Admiral (Contre amiral) Dominique-Marie Gauchet, commander of the Mediterranean Squadron (Escadre de la Méditerranée's) Second Division (2ᵉ Division de cuirasée) of the First Battle Squadron (1ʳᵉ Escadre de ligne). Together with four of her sisters, she participated in a large naval review by the President of France, Armand Fallières, off Cap Brun on 4 September and then the visit by the Navy Minister, Théophile Delcassé on the 8th. 
In mid-April 1912, the First Battle Squadron hosted three British armored cruisers at Golfe-Juan as their commander, Rear-Admiral Edward Gamble unveiled monuments to King Edward VII and his mother, Queen Victoria, at Cannes. Mirabeau participated in the July maneuvers in the Western Mediterranean and the exercise simulating a blockade of Ajaccio, Corsica, in November. On 3 March 1913 the First Battle Squadron conducted gunnery training off the Îles d'Hyères with the First Lord of the Admiralty, Winston Churchill, observing. The ship participated in combined fleet maneuvers between Provence and French Tunisia in May–June and the subsequent naval review conducted by the President of the Council, Raymond Poincaré, on 7 June. Rear Admiral Marie-Jean-Lucien Lacaze relieved Gauchet on 16 August and Mirabeau joined her squadron in its tour of the Eastern Mediterranean in October–December, making port visits in Egypt, Syria, and Greece. 
Lacaze shifted his flag to her sister Voltaire on 12 March 1914 and the ship had to briefly withdraw from the grand fleet exercises on 13 May due to engine troubles. As tensions rose during the July Crisis, Mirabeau and the other ships of the First Battle Squadron downloaded their practice ammunition and exchanged suspect lots of propellant for new ones beginning on 27 July. They recoaled four days later and the Marine Nationale mobilized on 2 August.
French battleship Mirabeau