Constantijn Huygens Jr. recorded in his diary that Gastigny told him on 23 March 1689 "that he did not want to stay in London, and that most of the hatred and anger befell the favourite.
In his will dated April 1708, he originally left £1,000 (equivalent to £202,945 in 2023) to benefit poor French Protestants – £500 for an infirmary and £500 for a pest house to be converted to a home for the aging.
Philippe Ménard, executor of Gastigny's estate, solicited for additional funds through public subscriptions for the hospital, known as La Providence.
The hospital opened in 1718 by royal charter, with Henri de Massue, Earl of Galway serving as its first governor.
[10] A painting of Gastigny by Pierre Mignard, circa 1680, is in the collection of the French Hospital, now on display in the Huguenot Museum in Rochester, Kent.