Although the Danton-class battleships were a significant improvement from the preceding Liberté class, they were outclassed by the advent of the dreadnought well before they were completed.
Mirabeau was 146.6 meters (481 ft) long overall and had a beam of 25.8 meters (84 ft 8 in) and a deep-load draft of 8.44 meters (27 ft 8 in).
She displaced 18,754 metric tons (18,458 long tons) at normal load and had a crew of 25 officers and 831 enlisted men.
While serving as a flagship, her crew numbered 31 officers and 886 enlisted men.
The ship was powered by four Parsons steam turbines, each driving one propeller shaft using steam generated by twenty-six Belleville boilers.
The turbines were rated at 22,500 shaft horsepower (16,800 kW) and were designed to provide a top speed of 19.25 knots (35.65 km/h; 22.15 mph).
Mirabeau slightly exceeded this figure when she reached a top speed of 19.7 knots (36.5 km/h; 22.7 mph) on her sea trials.
The ship carried enough coal to give her a range of 3,500 nautical miles (6,500 km; 4,000 mi) at a speed of 10 knots (19 km/h; 12 mph).

The main battery of the Dantons consisted of four Canon de 305 mm (12 in) modèle 1906 mounted in two twin gun turrets, one forward and one aft of the superstructure.
Their secondary armament consisted of a dozen Canon de 240 mm (9.4 in) modèle 1902 guns in twin turrets, three on each side of the ship.
A number of smaller guns were carried for defense against torpedo boats.
These included sixteen Canon de 75 mm (3 in) modèle 1908 guns in casemates in the sides of the hull and eight 47-millimeter (1.9 in) Hotchkiss guns mounted on the superstructure.
She was also armed with two submerged 450-millimeter (17.7 in) torpedo tubes, one on each broadside.
The ship's waterline armor belt ranged in thickness from 180 to 250 millimeters (7.1 to 9.8 in) and the main gun turrets were protected by armor 260–340 millimeters (10.2–13.4 in) thick.
The sides of the conning tower consisted of 266-millimeter (10.5 in) armor plates.
Although the Danton-class battleships were a significant improvement from the preceding Liberté class, they were outclassed by the advent of the dreadnought well before they were completed. Mirabeau was 146.6 meters (481 ft) long overall and had a beam of 25.8 meters (84 ft 8 in) and a deep-load draft of 8.44 meters (27 ft 8 in). She displaced 18,754 metric tons (18,458 long tons) at normal load and had a crew of 25 officers and 831 enlisted men. While serving as a flagship, her crew numbered 31 officers and 886 enlisted men. The ship was powered by four Parsons steam turbines, each driving one propeller shaft using steam generated by twenty-six Belleville boilers. The turbines were rated at 22,500 shaft horsepower (16,800 kW) and were designed to provide a top speed of 19.25 knots (35.65 km/h; 22.15 mph). Mirabeau slightly exceeded this figure when she reached a top speed of 19.7 knots (36.5 km/h; 22.7 mph) on her sea trials. The ship carried enough coal to give her a range of 3,500 nautical miles (6,500 km; 4,000 mi) at a speed of 10 knots (19 km/h; 12 mph).
The main battery of the Dantons consisted of four Canon de 305 mm (12 in) modèle 1906 mounted in two twin gun turrets, one forward and one aft of the superstructure. Their secondary armament consisted of a dozen Canon de 240 mm (9.4 in) modèle 1902 guns in twin turrets, three on each side of the ship. A number of smaller guns were carried for defense against torpedo boats. These included sixteen Canon de 75 mm (3 in) modèle 1908 guns in casemates in the sides of the hull and eight 47-millimeter (1.9 in) Hotchkiss guns mounted on the superstructure. She was also armed with two submerged 450-millimeter (17.7 in) torpedo tubes, one on each broadside. The ship's waterline armor belt ranged in thickness from 180 to 250 millimeters (7.1 to 9.8 in) and the main gun turrets were protected by armor 260–340 millimeters (10.2–13.4 in) thick. The sides of the conning tower consisted of 266-millimeter (10.5 in) armor plates.
French battleship Mirabeau