Laser plasma accelerators are currently able to produce ultra-short, quasi-monoenergetic and collimated electron beam of major interest for the study of ultra-fast phenomena, material science and medicine. A laser based accelerator designed to produce GeV electrons with 2% bandwidth and low emittance (0.02 mm mrad) is presented. This compact approach (cm scale for the plasma) and tens of meters length for the whole facility should permit a miniaturization and cost reduction of future accelerators and associated X-Free Electrons Lasers.