To avoid confusion with other members of the Cassini family (his father, son and grandson), he is sometimes known as Cassini II. Jean-Dominique Cassini was head of the Paris Observatory at the time of his marriage to Geneviève in 1674 and, two years previously, had become a French citizen, changing his name from Giovanni Domenico Cassini . Geneviève was the daughter of the lieutenant general of the compté of Clermont and they owned the Château de Thury in the Oise which became their summer residence.
Upang maiwasan ang pagkalito sa iba pang miyembro ng pamilya Cassini (kanyang ama, anak at apong lalaki), siya ay paminsan-minsan na kilala bilang Cassini II. Jean-Dominique Cassini ay ulo ng Paris obserbatoryo sa panahon ng kanyang kasal sa Genevieve sa 1674 at, dalawang taon na dating, nagkaroon na maging isang mamamayan Pranses, ang pagbabago ng kanyang pangalan mula sa Domenico Giovanni Cassini. Genevieve ay ang mga anak na babae ng tenyente heneral ng compté ng Clermont at sila ay pag-aari ang Chateau de Thury sa Oise na kung saan ay naging kanilang mga tag-araw na paninirahan.