The family, up to 1914 and onward, used Czenstkowski as the spelling of their name. Franziska changed this, attempting in 1915 to leave behind her eastern origins when living in Germany, and adopted Schanzkowsky. The family had been granted use of the honorific "von" a few hundred years earlier, but it was Franziska's father who finally abandoned it. She was born in West Prussia, and raised in Pomerania. The places are now in modern Poland but at the time of her birth-and for hundreds of years before-had been entirely in German hands.
For the most complete research into her family origins and background, I highly recommend "Resurrection of the Romanovs" by King & Wilson, which once and for all finally revealed much of the truth behind her.