Okay, that makes more sense (I was wondering why there were no news articles on it).
Josephine's ring sold for €730,000, or $948,000 at the Osenat auction house in Fontaineblue. It was from the Collection of Prince Victor Napoleon and his wife, the Princess Clementine of Belgium. The name of the buyer has not been released.
Prince Victor Napoleon (or, as per Wiki, Victor, Prince Napoleon) was the Head of the House of Bonaparte from 1879 until his death in 1926. His grandfather, Jerome-Napoleon Bonaparte, King of Westphalia, was Napoleon's youngest brother. The current Head of the House is either Victor's grandson, Charles, or great-grandson, Jean Christophe, as there's somewhat of a debate on the matter. Presumably, it was one of them who decide to sell the collection.