This bite-size museum offers a bite-size taste of the finer side of 18th-century France. Its founder, Ernest Cognacq, led a rags-to-riches life: At 12 years old, he was selling odds and ends as an itinerant merchant, and by the end of his life he was the owner of a fabulously successful department store (the now-defunct La Samaritaine) with a prodigious private art collection. His rich assortment of 18th-century art and furniture make up the contents of this small museum, which is housed in a lovely hôtel particulier (mansion). The collection leans heavily toward the romantic side of the century, with many lesser works by famous artists such as Chardin and Fragonard, but what’s most impressive here is the furniture, such as the bed à la polonaise draped in blue damask and framed in gilt, or the exquisite Louis XVI–era writing table with geometric wood inlay.