Mark Twain first visited Paris July 6, 1867 as part of his "Innocents Abroad" excursion. In late February of 1879 he returned with his family and stayed until July. "The weather was miserably cold; he suffered from rheumatism and dysentery and spent most of his time in bed." Again in June of 1891, he passed through the city returning three years later for a stay of from March until June of 1894, then from October 1894 through May of 1895. (Mark Twain A to Z)

GALAXY, November 1870 MARK TWAIN'S MAP OF PARIS.
"I published my "Map of the Fortifications of Paris" in my own paper a fortnight ago, but am obliged to reproduce it in THE GALAXY, to satisfy the extraordinary demand for it which has arisen in military circles throughout the country. General Grant's outspoken commendation originated this demand, and General Sherman's fervent endorsement added fuel to it. The result is that tons of these maps have been fed to the suffering soldiers of our land, but without avail. They hunger still. We will cast THE GALAXY into the breach and stand by and await the effect." [ http://www.twainquotes.com/Galaxy/187011a.html ]

See Paris and Its Environs, Bædeker 1878