Précieuse (French for precious) is the sword of Baligant, the Saracen king in the French epic The Song of Roland.
Baligant allegedly named his sword in response to hearing that Charlemagne's sword had a name. Throughout the epic, there are several contrasts between the two, with Baligant being portrayed as a foolish counterpart to Charlemagne. Baligant felt inferior, and so named his sword with a similar name.
References
Précieuse Wikipedia(Text) CC BY-SA