Secondary objectives: overall comparison of 2 strategies of continuous use of RT CGM vs conventional SMBG on HbA1c ; to evaluate their effectiveness on others parameters of glycemic control (hypoglycaemias, ketoacidosis, glycemic variability); to evaluate impact on glycemic control of different factors including percentage of effective time of wearing the sensor; to evaluate : skin tolerance, acceptability of the device; quality of life and satisfaction to the use of the device; and medico-economic impact of the use of the device.