Henri Meilhac (1831-1897) was a French dramatist and opera librettist. He frequently collaborated with Ludovic Halévy (1834-1908), an author and dramatist. Ludovic's uncle, Fromental Halévy (1799-1862) was known as an opera composer.

The comma bacillus, which causes cholera, was discovered in 1849. Proust's father Adrien, a doctor, worked at combating the disease and is known for his application of the cordon sanitaire as a means of preventing its spread. The comma bacillus is thus named as a result of its curved shape, which is similar to a comma without the 'head'.

La Princesse de Clèves is a French novel which was published anonymously in 1678. It is thought to have been written by Madame de La Fayette. Despite being married to the Prince de Clèves, the heroine falls in love with Duc de Nemours. Although they do not consummate their love, the jealously of her husband forces the Princess to choose between duty and love even after his death.

René is a novel by François-René de Chateaubriand (1768-1848), who is considered to be the father of French Romanticism.

Antoine-Laurent de Lavoisier (1743-1794) is considered the 'father of modern chemistry'. He was a French noble, and was guillotined during the Revolution. 

André-Marie Ampère (1775-1836) was a French scientist who is regarded as one of the main discoverers of electromagnetism. The electricity measurement, the ampere (amp) is named after him.

 

There is a Vermeer study called Diana and her Companions, so Swann seems to have been right about this.