  We present the result of multi-wavelength observations of the microquasar GRS
1915+105 in a plateau state with a luminosity of ~7.5x10^{38) erg s-1 (~40%
L_Edd), conducted simultaneously with the INTEGRAL and RXTE satellites, the
ESO/NTT, the Ryle Telescope, the NRAO VLA and VLBA, in 2003 April 2-3. For the
first time were observed concurrently in GRS 1915+105 all of the following
properties: a strong steady optically thick radio emission corresponding to a
powerful compact jet resolved with the VLBA, bright near-IR emission, a strong
QPO at 2.5 Hz in the X-rays and a power law dominated spectrum without any
cutoff in the 3-400 keV range.
