A process for production of lignins and synthetic gas including the steps of extracting lignins and hemicellulose by putting solid Lignocellulosic Raw Material in contact with a mixture of water and formic acid at atmospheric pressure and at a temperature between 80° C. and 110° C.; fractionating, the primary solid fraction and the primary liquid fraction; separating the lignins from the intermediate liquid fraction; and gasifying at least part of said primary solid fraction and/or at least part of said residual liquid fraction for producing synthetic gas.