Jumping to conclusions

This morning, I came across a phrase, from the beginning of a case in Maigret (reference 1), when everything is still something of a muddle, 'Un clou chasse l'autre' (page 250), which I read to mean one clue coming in fast after another, all something of a muddle indeed. Aha, I thought. The French 'clou' for nail is clearly the origin of our word 'clue'.

I get some support for this from Larousse, which tells me of various meanings and uses for the word. Lines of nails, for example, were used to mark crossings on roads (clouté) before the invention of white lines. One supposes that one used rather large nails for this purpose and that one was then able to follow the line of nails. By extension, one followed one clue to the next. But no support from Littré.

Not to be put off so easily, I turn to OED, in which I read that 'clue' is a corruption of 'clew', a very old word, not French at all, meaning, among lots of other things, the ball of thread with which one finds one's way out of the labyrinth. Hence Agatha's sort of clue and nothing whatsoever to do with nails.

Perhaps as a consolation prize I can claim some convergent evolution? That Simenon, who probably knew the English word, was happy to use the French word with a similar intent?

Reference 1: Le Voleur de Maigret - Simenon - 1966 - Volume XXIV of the collected works.