Sophie Calle

French artist Sophie Calle often creates situations that allow her to investigate other people's lives.

In the series "The Hotel" (1986), she took a job as a housekeeper and took photos of other peoples' belongings, eavesdropping while she cleaned.

In another piece called "The Sleepers" (1979) she asked people to come sleep in her bed for 8 hours, each person replacing another, photographing them every hour and writing down everything they said.

And in 1983, the newspaper "Liberation" offered Calle 1/2 a page a day for the summer for a project. Calle used an old address book she found on the street, visiting each people listed inside asking them to tell her about the owner.

See a list of her projects in Wikipedia.