His trousers look a little bit like someone just lopped off a pair of modern ones and the fabric is WELL off, but the cut of the coat and the waistcoat is pretty good! I'm just not convinced they're from the same eras >.0
For the coat, I'm inclined to say circa 1760-80 - I thought towards the end of that period but they seem to all have turnback cuffs past 1770, so the sleeves are most certainly 1760-ish, but the cut of the coat is also fuller at this time and gets more streamlined as the century moves on, judging by the size view I'd be inclined towards the 1780's for this one... so, er, mix and match maybe? - and aside from the belt (Is that a belt?) the breeches from that period are not a bad match either. They're fairly loose (By the 18th Century in France standards) which makes me lean towards the earlier estimate (1760)
The waistcoat is also historically accurate, just to a completely different style (I'm tempted to say a different century). 18th century waistcoats tended to be long, whereas his finishes very neatly at the waist The prominent centre line as well makes me think you'll find the closest match circa the 1830's. It's a REALLY decent 1830's waistcoat, I'm just not quite sure why it's paired with a 1770's suit O.o
The V&A and the Kyoto Costume Institute both have really good collections of men's clothing from these periods (Although the KCI's men's stuff drops off at the end of the 18th century), some of which is online, so I recommend their websites/publications if you want to have a rummage and draw your own conclusions.
((... French rock opera, you say?