Perret tower, Observation tower in Paul Mistral Park, Grenoble, France

Perret tower is a reinforced concrete observation tower in Grenoble's Paul Mistral Park, octagonal in section and 95 metres tall to its lightning rod, with a diameter of 8 metres at the base. Eight vertical pillars form the frame, and the shaft is filled with prefabricated openwork panels of 60-centimetre plates pierced by small triangular openings. A circular balcony at 60 metres rings the tower, and the topmost openwork section holds the spiral staircase of 484 steps.

Auguste Perret designed the tower for the 1925 International Exhibition of Hydropower and Tourism; it was built between 20 May 1924 and 4 May 1925, the first reinforced-concrete tower in the world. It was the exhibition's orientation tower and symbol, and the only structure from the event still standing. Closed to the public from 1965, it was listed as a monument historique in 1998 and reopened in July 2026 after restoration work carried out from 2022 to 2026.

The tower's name honours Auguste Perret, its architect; the art critic Marie Dormoy, who invited him to Grenoble, became the tower's godmother. It was first called "the tower for looking at the mountains". The orientation table requested by the Touring Club de France rings the tower at the 60-metre level, not the summit, and helps visitors name the Alpine peaks.

The tower sits inside Paul Mistral Park, which makes it easy to combine a visit with a walk in the park. Clear days offer the best views, so mornings in winter and late afternoons in summer tend to give the sharpest sight of the mountains.

When the elevators first ran at the 1925 opening, a group of official guests got stuck inside during one of the early rides, causing quite a stir. In its early years, the tower also broadcast radio programs to the city from its top, making it one of the first structures used for wireless transmission in the region.