Tour Denecourt in Fontainebleau. June 2018. For more information about it check Denecourt and his footpath (in French) and a stub in the local Wikipedia about the tower. The latter states the tower was destroyed in 1878 in an earthquake. Well… not sure about Fontainebleau being on the San Andreas fault yet. But other sites concur with this view.
This stone tower was built in 1851 by Fontainebleau forest lover Claude-François Denecourt on the westernmost top of the ridge known as Rocher Cassepot. It was originally named Fort L’Empereur [Editor’s note, i.e. “the Emperor’s Fort” because Denecourt was an ex soldier of Napoleon’s Army]. The tower had no military purpose, it served as a vantage point. It collapsed in 1878 and was rebuilt by Colinet (via a fundraising campaign as stated on a plaque). It was subsequently renamed Tour Denecourt. [blog source]
As to the earthquake of 1878, Fontainebleau photo evokes memories of an earthquake that struck the whole Seine Valley on January 28, 1878. The only evidence I could find of a tremor on that day in France was one which had its epicentre in Normandy, hundreds of miles to the North-East. Yet, it’s not at all impossible that aftershocks happened in other remoter places.