Jan. 29 (Bloomberg) -- Fabienne Jeanmonod and her family dropped anchor along the shores of Lake Geneva two summers ago looking forward to a quiet picnic. After three minutes on shore, a man appeared from the surrounding fields, screaming that they were trespassing. She meekly packed up and left.

That incident turned the 47-year-old mother into an activist. Jeanmonod joined Rives Publiques, a citizens' group demanding that Swiss localities enforce the public's right to walk along the shores of the country's 1,484 lakes. Access is being obstructed as rich residents such as America's Cup sailing champion Ernesto Bertarelli build waterfront mansions.

``We were in a horrible situation,'' says Jeanmonod, an executive assistant at a Lausanne-based engineering company, recalling the confrontation. ``He was aggressive and we tried to calm him down. But if we'd known we were within our rights, we wouldn't have excused ourselves.''

Lake Geneva, Switzerland's biggest body of water, has become the main battleground. Rives Publiques is asking local authorities to reject Bertarelli's plans for a private dock at his property, saying the project violates a right dating from 1907 that guarantees public access to all Swiss shorelines.

The billionaire's spread is leased to the U.S. Ambassador to the United Nations in Geneva, Warren Tichenor. The property, patrolled by U.S. security guards and Swiss soldiers behind stone walls and an unmarked iron gate, also contains a house leased to UEFA, European football's ruling body.

A spokesman for Bertarelli's office in Geneva who didn't want to be named declined to comment for this story.

Court of Human Rights

Rives Publiques says that other celebrity property owners, including former Formula One racing champion Michael Schumacher, also trample on shoreline access rights. Schumacher's spokeswoman, Sabine Kehm, declined to comment.

``It's wrong to take away that right from 7 million people and to give it to a few thousand rich,'' says 64-year-old Victor von Wartburg, who started Rives Publiques in February 2003. The group says it may go to the European Court of Human Rights to force the Swiss government to act.

Von Wartburg, a retired businessman, says he has been chased off every property where he tried to land his boat on the shores of Lake Geneva. He says he has been threatened with dogs, and ``in one case, a guy came at us with a hunting rifle.''

Some property owners say the fight is driven by class envy.

``This is all about jealousy,'' says Christoph Sauter, 65, a retired lawyer who owns a lakeshore house in the Zurich suburb of Kuesnacht, complete with an old wooden row boat. ``They don't want us to have more than they do.''

Legal Tangles

Part of the debate centers on how much of the shoreline should be public, since the lake itself cannot be privately owned. Rives Publiques argues that tourists and locals alike should have access to a 3-meter (10-foot) strip of land free of obstacles above the waterline.

Swiss law states that improving public access to lakes and rivers is an objective or ``principle,'' says Etienne Poltier, a professor of public law at the University of Lausanne. That goal may be balanced against other aims, such as the need to protect a nature reserve, but not the privacy concerns of shoreline residents, he says.

Part of the problem is Switzerland's network of independent jurisdictions. The nation is a federation of 26 cantons, along with 2,758 regional districts, or communes, and each level of government has the power to enforce planning laws, including waterfront access. Cantons don't enforce the rules, partly because they compete for rich taxpayers, says Pierre Alain Rumley, head of the Federal Office for Spatial Development.

Public Path Fight

The canton of Zurich plans to introduce recommendations for a public walkway along Lake Zurich's shoreline, only 40 percent of which is accessible to the public. Waterfront residents say such a path will let tourists invade their private gardens.

A shoreline trail would be too expensive for taxpayers and is unnecessary because there are plenty of spots to gain access to the lake, Sauter says. He plans to ``fight'' the construction of a path and would build a screen to protect his privacy if it is ever introduced.

The canton of Vaud, whose biggest city, Lausanne, lies on the northern shore of Lake Geneva, guarantees access to the shoreline for fishermen, barge haulers, customs officers and police. However, the law isn't enforced, Von Wartburg says.

Public pressure has raised awareness of access rights, even though it's unlikely public walkways will be built in front of billionaires' homes, says Daniel von Siebenthal, president of the Vaud canton's lakeshore commission, which makes preliminary decisions on building requests.

Much Stricter

``It always was difficult to build on the shore, but now we tend to be much stricter because we're aware that there's a real drive toward insisting on improving access,'' he says. ``To move to the next step of actually building paths takes a very long time, because of all the negotiations it involves with owners.''

Jeanmonod, the Rives Publiques activist, now keeps a printed copy of the law granting public access on her boat to brandish at outraged homeowners.

``We only want somewhere to land from a boat so we can picnic and swim,'' she says. ``If we can't stop now and then, we may as well leave the boat in the port.''

-- With reporting by Daniela Silberstein, Christian Baumgaertel and Joseph Heaven in Zurich. Editors: David Ellis, Willy Morris.

Last Updated: January 29, 2008 07:49 EST