If you can lightly skip over his take on the Revolution (he knows a lot about guillotines, but evidently not much about the 1790's!) the history page has a pre-1925 fire photo of the Paris guillotine blade and lunette. There was a fire in 1925 that destroyed Madame Tussauds in London, including, sadly, most of the Revolution and Napoleon artefacts, but the blade survived, though damaged - I don't know what became of the lunette (I last went when I was 5 or 6!). I suppose you have to take their word for it that it's the one: it's now billed as 'the blade that killed Marie-Antoinette' (and I bet they were tempted to add 'like in the movie'?), but if that's the case parts, if not all of it, must also have been used to kill - well, pretty well everyone that everyone here is interested in...which is a weird and horrible thought...
(btw in case you didn't know, Tussaud also allegedly took Robespierre's 'death mask' -the Parisian place that makes copies believes it was actually taken in life, which is plausible - Washington had his cast in life, as did many politicians, poets etc. - but billing it as taken at the foot of the guillotine sounds more dramatic! http://www.guardian.co.uk/world/2007/dec/01/france.art )
Gosh, I'm morbid today!