Abstract : Piton de la Fournaise is one of the most active volcanoes of the Earth. Since mid-2003 14 eurptions occurred. We performed a continuous InSAR monitoring of this period of intense volcanic activity using ASAR-ENVISAT data. Computed interferograms provide a precise measurement of volcano displacements. This study highlights the high potentiality of InSAR as an operational monitoring tool at Piton de la Fournaise. Furthermore, InSAR data were used to determine the characteristics of superficial dykes that fed eruptions and of the magmatic storage system. We modeled the data using a 3D-Mixed Boundary Element Method combined with a Monte-Carlo exploration algorithm. Most of co-eruptive displacements associated with proximal eruptions can be explained by 45° to 70° eastward or sub-vertical dipping dykes, which root at ~1500 m a.s.l..