A ban on smoking in enclosed public places has come into effect in Lebanon, prompting sit-in protests by some restaurant and cafe owners.
The ban covers bars, restaurants and cafes where traditional shisha, or hookah, water pipes are ubiquitous.
The law was passed last year and already affects airports, schools and hospitals.
Anyone who breaks the ban faces a $90 (£57) fine. Cafe owners who turn a blind eye could be fined up to $2,700.
Smoking, which is banned in public in much of Europe and the United States, is very popular in Lebanon.
Daily smoking is more prevalent among adults in Lebanon than in any other country in the Middle East, according to World Health Organization (WHO) figures from 2009.
More than 45% of men and 30% of women are estimated to be regular smokers.
Neighbouring Syria became the first Arab state to enforce a smoking ban in April 2010.
Under the law, advertising and sponsorship by tobacco companies is also banned, while 40% of the surface area of a cigarette packet will have to be covered with health warnings.
In Beirut, one shisha smoker told the AFP news agency the ban was a "European concept".
"Shishas are a way of life in eastern Lebanon and they want to deprive us of that," said Saad Fiefel, smoking outside a cafe.
Some retailers have said the ban will force many cafes to close down because so many rely on shisha smokers for business, and customers will not always be able to sit outside.
One coffee shop owner in Beirut's Hamra district told AFP: "Nearly 80% of our customers come here for the hookah. How will we do in winter when there won't be any terraces?"