Who crossed out and why some passages of the letters that Queen Marie Antoinette sent to her favorite, Count Axel von Fersen? And what did these paragraphs say? While she was imprisoned at the Tuileries, the wife of Louis XVI wrote, between June 1791 and August 1792, nearly 50 letters to the Swede Von Fersen, a military man and ambassador, who a year earlier had helped organize the frustrated flight to Varennes of the members of the royal family.The French National Archives, owners of the letters, tried for years to figure out what those parts hidden under black ink said. They even resorted to police forensic units. But it was all in vain until they requested the services of Anne Michelin, a chemist at the Centre for Research and Conservation in Paris. In October 2021, she and her team published the results in the journal Science Advances.The hidden paragraphs seem to support the theory that Von Fersen, in addition to being Marie Antoinette's favorite, was her lover. This is implied by fragments such as “not without you”, “you, whom I love and will continue to love”, “you make my heart happy” or “tender friend”, with adverbs such as “madly”, which denote romantic passion. It is not surprising, then, that someone wanted to prevent these paragraphs from being read. It was believed to have been a relative of the queen, but Michelin's team also found the answer: it had been Axel von Fersen himself.