Paris - France on Wednesday made paying for sex a crime - a radical change of approach in a country where brothels were once legal.
Prostitutes' pressure groups are divided about the new law.
Some welcome the fact that, in future, the clients not the sex workers will be treated as criminals.
Other prostitutes demonstrated outside the National Assembly on Wednesday, complaining that they will be forced to work in even greater secrecy and that they will lose their more “respectable” and non-violent customers.
“We will simply face more poverty, more violence and more stigmatisation,” said Morgane Merteuil, spokeswoman for Strass, one of several sex workers' unions in France.
The lower house of the French parliament approved the new law at its fourth reading yesterday after a three-year battle with the upper house or Sénat. In future, anyone who is proved to have paid for sex will face a €1 500 (£1 200) fine, rising to €3 750 for a second offence.
The law also provides financial support for prostitutes who want to create new lives. It will permit foreign sex workers to remain legally in France, so long as they abandon prostitution.
A law passed in 2003 which criminalised “passive” street soliciting - in other words wearing skimpy or provocative clothes - was repealed.
The estimated 40 000 prostitutes in France, eight out of 10 from Africa, Asia or Eastern Europe, can now offer their services openly on French streets or on the internet but it will be illegal to approach them.
This is the latest in a series of attempts to regulate prostitution in France since licensed brothels or “maison closes” were abolished in 1946.
France becomes, after Sweden, Norway and Iceland, the fourth country in Europe to transfer punishment to the client.
The Socialist deputy who first proposed the law in 2013, Maude Olivier, said the penalisation of customers would “reduce demand” and allow prostitutes to be considered as “victims and not offenders”.
The health minister, Marisol Touraine, said it would “force men to think about what they do and the way they behave”.
Grégoire Théry of the prostitutes' support group, Mouvement du Nid, said the law would “finally end the impunity of clients”.
Three previous attempts to push through the new law were rejected by the centre-right dominated upper house of the French parliament.
The Sénat has now exhausted its constitutional rights of amendment and delay.
The previous French laws on prostitution were similar to those in Britain - and enforced equally patchily.
It was illegal to run a brothel or to be a pimp or to solicit in public. It was not actually illegal to sell or buy sex.
Under the new law, pimping and brothels remain illegal. It is legal to offer sex for sale but illegal for someone to buy it.
Police unions have campaigned against the changed approach. They say it will be difficult to enforce because financial transactions between prostitute and client will be difficult to prove.
The clients fear of punishment or publicity will nonetheless force prostitution further underground, police say.
This will make action against the international prostitution networks, a €2bn a year industry in Europe, even tougher.
The Independent