I'm always a bit wary with these. Even the more familiar models we know from catalogues - all the components needed to assemble the watches were being freely sold on the German market in the late 90s and early 2000s, and if they were there, I don't doubt they were in other countries too.

It's such a shame that these don't confirm to any of the known Heuer reference number schemas, or to the usual serial number ranges - they are both very useful diagnostic tools. Take the Monaco case AndyO links above for example - the serial number stamped would be from about 1986 or 1987 extrapolating forward from numbers we do know, long after they stopped making the Monaco. That's one of the reasons I wouldn't be keen on a serial numbers register - it gives more ammunition to the fakers and takes away one of our tools for spotting originality at a glance. But we can't use those here as the factory watches of this type don't fall into the known ranges.

So we fall back to looking at the details, as Stewart has done below:

I have some concerns about that caseback too - I'd expect the brushing to be all in the same direction and level, but there appears to be some deeper marks that are less horizontal than the general finish. Looking at that and the earlier picture:

too, the brushed finish doesn't run right to the edge of the flat plane as I would expect it to on a Heuer. There seems to be a bit of a border rather than running right to the edge. The white fibres on the sticker are unusually prominent - might have been soaked off, the caseback refinished then the sticker reapplied?

Looking at the second photo makes me question whether the case is PVDed or just painted? Or potentially painted over an earlier PVD layer - the chip near the bottom pusher seems to show an earlier layer of black material under the top layer? And where the caseback meets the case looks odd too - looks more like silver paint with lines along it than steel. Is the main case definitely steel, or could it be chrome-plated base metal?

Looking at the dial, we're searching for familiar details from other examples of this type of watch. I'll borrow one of Revorbaro's pics from Vetroplastica, hope he doesn't mind!

We're on firmer ground here. The tachy scale looks the same, as do the markers. The distinctive shape of the chrono needles is also present and correct. The handset differs apart from that, but we've seen a few different types of hands on these (which is a slight worry). Revorbaro's watch has a black date wheel, but we've seen red dates on these before too. The "Made in France" versus "Ebauche Suisse" thing isn't a problem - the earlier watches carry "Ebauche Suisse" to stress the link with Switzerland before later watches come clean with "Made in France". The acid yellow and black combo is new on me, but as Stewart suggests could be a customer special. Anyone know a company with those colours and no recognisable logo to put on the dial?!

There is so much that is mysterious about these watches at this period of production, it's hard ever to be sure. I posted some positives and some negatives there, but I think on balance I'd still reserve judgement!