A more thorough explanation:

The unity of art refers to the inseparable connection between the functional and aesthetic aspects of applied art. In other words, it is the idea that art and design should not only be visually pleasing but also serve a practical purpose.

For example, a chair can be considered a work of art if it is not only beautiful but also comfortable and functional. Similarly, a building can be seen as a piece of art if it is not only visually appealing but also provides a safe and comfortable space for people to live or work in.

In France, the unity-of-art approach is used to protect applied art and industrial design. However, they do not extend copyright protection to strictly utilitarian designs.

Overall, the unity of art emphasizes the importance of combining form and function in design to create objects that are both beautiful and useful.