The ad on the French finance ministry website is deadpan and succinct: “For sale: late 19th century prison in the centre of Grasse, 1,277.42 square metres (13,750 square feet). No garage or parking space. Needs renovating.” Prospective buyers of the site in southeast France are required to lodge a deposit of 50,000 euros ($56,000). There are around 10 such notices for defunct prisons on the website, testament to a growing trend that has seen many…