The Calibres de France ("French calibers") was a system of standardization of cannons in France, established by King Francis I of France from about 1525.^[1] The objective was to simplify and codify cannonry, in order to facilitate production.^[1] On 26 September 1526, Francis I wrote about the artillerye de mon calibre ("Artillery of my caliber"), and an even earlier mention is known from 1512.^[1] The Calibres de France were formalized in an ordinance of 1552.^[2]

Six standard sizes were defined: the cannon (Canon), the "grand" culverin (Grande couleuvrine), the "bastard" culverin (Couleuvrine bâtarde), the "middle" culverin (Couleuvrine moyenne), the Falconet (Faucon), and the (Fauconneau).^[1]

The system was expanded by an ordinance dated 27 November 1572, and an edict dates December 1601.^[1]

The 6-guns Calibres de France system was still in place at the time of Louis XIII, which was later developed to an 18-guns system.^[3]

The system was phased out with the Keller system in 1666, and the De Vallière system on 7 October 1732.^[3]

• "Grande couleuvrine" of Francis I, caliber: 140mm, length: 307 cm, recovered in Algiers in 1830.
• "Grande couleuvrine" of Francis I with Salamander emblem and inscription in Arabic, Siege of Rhodes (1522).
• "Couleuvrine bâtarde" of 1548, with arms of Henri II and Catherine de Medicis and crescent of Diane. Caliber: 85mm, length: 300 cm, weight: 1076 kg.
• Bronze culverin of Francis I.
• Grand culverin of the Knights Hospitallers, 1500-1510, Rhodes. French work, caliber: 165 mm, length: 540 cm, weight: 3,343 kg, ammunition: 15 kg iron ball. Arms of Grand Master Emery d'Amboise. Given by Abdülaziz to Napoleon III in 1862.