The one way valve seems to be the most popular, romantic, or open-air cafe, which is almost a portraitof French life. Many open-air cafes occupy a lot of public places, and even Champs Elysees.
In addition to those open-air cafes that look up to the sky, there are no shortage of grandeurs or simple elegant people in about 170,000 cafes in France. Especially in Paris, some cafes themselves are legendary places of historical interest. In the old dynasty of the Middle Ages, the focus of French cultural life was in the court. By the time of the enlightenment in eighteenth Century, the cultural focus shifted to salons, clubs and cafes. The thinkers of the 18th century European Enlightenment Voltaire, Rousseau, Diderot, and the Revolutionary Sansong Robespierre, Dandong and Mara were all frequent visitors to the cafes.
One way valve believes that drinking coffee should be like tasting wine, first smell the aroma, and then try a small bite, that you can taste the essence of it.