The German government argued it worked, and defended it to the end.

“Of course there's the danger that a convict could stay in preventive detention for the rest of his life," admitted Wolfgang Shild, Saarland Secretary of State for Justice. “But to avoid this situation we have frequent specialist checks to assess their condition.”

Anti-Paedophile campaigner Thomas Bruckman opposes preventive detention. His alternative, however, is longer sentences in the first place.

Last year, another sex offender who avoided preventive detention was released back into his community – a move that still causes angry protests. Now these fears are being replicated across Germany.

“A few of these criminals will repeat such crimes again,” Bruckman insisted. “That's the worst thing that could happen and it probably will happen because they weren't put away.”

It costs far more to keep offenders under guard in the community than behind bars. The German newspaper “Bild” put the figure at 12,000 euros a day compared to 100 euros a day in prison.

This may be a large price to pay when lawyers insist that the option hardly provides the freedoms of daily life.

“If he goes into a shop, there's always two people following him. If he goes to a doctor, two people are next to him,” said Walter H’s lawyer, Michael Rehberger. “And it is impossible to have a normal life.”

As Michael Rehberger fights for greater freedoms for Mr. H., criminals' rights remain of little worry to most Germans anxious about the safety of their own families.

An estimated 200 potentially dangerous prisoners could soon be released across Germany. And while that might ease consciences in Strasbourg, it does not ease anyone's nerves in Germany.