Literal translation
it's a tale of Master Arnaud
Meaning
it's a tall tale, hard to believe
Explanation
The expression attributes an implausible story to a certain Mèste Arnaud, a popular storyteller figure invoked here as the very type of a fanciful tale devoid of any serious foundation, following the same pattern as other playful proper names coined by Provençal speech to describe attitudes or remarks without targeting any real person. Calling a story a tale of Mèste Arnaud amounts to labeling it a cock-and-bull story, a barely believable account, or a fable made up to amuse or deceive. The name Mèste Arnaud does not appear as such in the dictionary, only Arnaud being listed as a plain first name, confirming the purely traditional and oral nature of this figure, passed down from generation to generation without leaving its own lexical trace. The expression relates, within the same set, to the one evoking Mèste Moucho, both phrases drawing on the same stock of fictional characters typical of Provençal popular wisdom. The register is familiar, used with irony to discredit an exaggerated or unconvincing story.