Petite toile, belle toilette

In the Middle Ages, a small, fine cloth or toilette (towelette) was used to cover clothing as a protection from insects and dust. The various and sundry articles necessary for a woman's or a man's personal grooming and embellishment were also wrapped inside such a small cloth and tucked away  when not in use, to be laid out in the morning when it was time to dress.   

Abraham BosseLes Cinq Sens, v. 1638 : La Vue

By the 17th century the "little cloth" might be of plain or decorated linen, or it could be a luxurious silk or sometimes even a small tapestry served as a wrapper for these necesary items. Now, the cloth, its contents, as well as the process were known as la toilette.

Jean-Francois de Troy Dame à sa toilette recevant un cavalier

"J'avais ce matin un Provençal, un Breton, un Bourguignon, à ma toilette," 

Mme Sévigné.

Boucher

Little by little, in the 18th century, the piece of furniture supporting the toilette 

very naturally became known as the table de toilette.

Elle passe des heures à sa toilette!

Clothing and all manner of finery being  part of the process from the start,
a lady's dress once worn took on the same expression, la toilette.

The room cabinet de toilette and toilettes (ladies'/men's room) came later
but then someone put a halt to the spreading of the word before everything was called toilette!

Avec le rare sentiment d'harmonie qui les caractérise, les femmes ont compris qu'il y avait une sorte de dissonance entre la grande toilette et la figure naturelle.

Avec le rare sentiment d'harmonie qui les caractérise, les femmes ont compris qu'il y avait une sorte de dissonance entre la grande toilette et la figure naturelle.

With the rare feeling of harmony that characterizes them, women have realized that there was a kind of dissonance between the elegant toilette and the natural state.

Théophile Gautier  La Peau de tigre 

photo St Tyl

Embroidered linen  toilette from 1640 , Musée de la Renaissance at Ecouen

for another cloth that gave a name to a piece of furniture, here

and a very particular table de toilette, here