PARIS » Aggravated robberies are up more than 40 percent in the Paris public transport system, and the government places blame for the rise on the attractiveness of smart phones.

The interior minister, Brice Hortefeux, calls it the "iPhone effect," and the police talk of thieves’ "going to pick apples" on the Metro. While Metro thieves seem to find iPhones particularly attractive, usually fetching at least $200 and sometimes as much as $400 on the street for some upgraded versions, smart phones in general have become a favorite target, the police say.

Such thefts drove a new wave of violence in 2010 on Paris subways, buses and suburban railways, according to Interior Ministry figures released last week. Thefts without violence were up 10 percent.

The Paris police chief, Michel Gaudin, said at a City Council meeting in December that "almost one of every two thefts on public transport now concerns a mobile telephone, while ‘classic’ wallet or purse thefts represent only 33 percent of incidents."

In November alone, the ministry said, of 2,813 objects reported stolen on Paris regional transit, 1,395 were cell phones, nearly 50 percent of the total, and of those, 64 percent were smart phones. The latest two models of the Apple iPhone made up nearly 28 percent of all stolen phones.

Inspector General Alain Gardere, director of security for a new police force charged with fighting delinquency in Paris and the suburbs, said that "the fashion for smart phones, with high prices, generates an increase in cases of thefts, more often violent. And the phenomenon has grown even further with the iPhone 4, which is much in demand."

While guns are rare in Paris, violent thefts sometimes involve knives and "poings americains," the French name for brass knuckles. Often, phones are grabbed quickly out of a victim’s hands as the subway car doors are closing; robbers tend to work in small groups, so that a stolen phone can be quickly passed to someone else to prevent an easy chase by an outraged victim.

The police say that many of the thieves are young men from the poorer banlieues, or suburbs, that ring Paris and who are looking for "thefts of opportunity." In leaflets and announcements, the police urge passengers "to use a minimum of prudence when using the touch screen of their smart phone."

The police said they could not estimate how many phones were stolen without being reported.

There have been very few deaths related to smart phone thefts, but one in late December attracted much media attention. A 27-year-old woman died in December after hitting her head, after a thief she was chasing pushed her violently down the stairs of a Metro station. Two days later, an old woman was put into a coma by a 14-year-old thief who knocked her over in a Metro station.

Video surveillance of transit was increased significantly last summer, the police said, having told the newspaper Le Figaro that about 25,200 cameras were in place in the Metro, suburban railways, buses and trams.

Some lawmakers are urging a law requiring telephone operators to create a system to permanently block the use of a phone after a theft, and not just the phone number itself. If the phones are made useless, these legislators argue, the market for stolen phones will shrink.