Anyone who has been to Chambray lès Tours looking at bathrooms (or indeed anyone who leaves the A10 in Tours to drive to Preuilly) will have noticed this construction in the middle of the road opposite Conforama. I realised immediately (mainly because of my avid readership of Hornblower books as a boy) that it was a semaphore/telegraph.
When we were looking at bathrooms yesterday we happened to do a U turn around the base of the telegraph, and I noticed it had a sign explaining what it was: "Telegraph Cl. Chappe".
Claude Chappe was born in Sarthe (not a million miles away from Tours, coincidentally) in 1763, and with his brother Ignatius worked on a number of different schemes for transmitting messages long distance. This telegraph shown here was the third such scheme and was invented in 1793. By 1852 the telegraph system covered most of the main cities in France, and was capable of sending a message vast distances in a very short time - Lille to Paris, for instance took 9 minutes under optimum conditions.
This semaphore seems to be in position 34: there is more about the code here.