Are Cartier Hotels and Jewelry the same company?

They are not a company.

According to information on Cartier’s official website, Cartier Hotel is a hotel brand under the famous French luxury brand Cartier, providing high-end luxury hotel services. Cartier Jewelry is the department of Cartier that specializes in jewelry and watchmaking and is world-famous for its unique design and exquisite craftsmanship. Although both companies are named after Cartier, they belong to different industries and business areas.