Inclusion Criteria:  Age: 6-65 years old Diagnosis of persistent asthma  Treatment level at study entry:  For children 6-11 years: Step2 or Step3 of the GINA document For adolescents and adults 12-65 years: Step2 under daily low-dose inhaled corticosteroids (ICS), Step 3 or Step 4 of the GINA document Uncontrolled asthma (ACQ-5 > 1.5) that, according to the physician, does not warrant an immediate step-up of the treatment History of moderate or severe exacerbations in the twelve (12) months prior to baseline visit  Exclusion Criteria:  Use of oral, rectal or parenteral glucocorticosteroids 30 days before enrolment Treatment with leukotriene receptor antagonist (LTRA) Treatment with maintenance and reliever therapy (SMART/MART) Smoking, current or previous with a history of 10 pack-years or more Documented COPD or other concomitant clinically important diseases or cognitive impairment that, according to the physician, may interfere with the subject's ability or safety to participate in the study Obesity (for subjects 6-19 years: BMI ≥ 95th percentile; for adults 20-65 years: BMI ≥ 40kg⋅m-2 For school-age children (6-11 years old): gestational age at birth < 37 weeks or documented bronchopulmonary dysplasia (BPD) Prolonged absence from home during the monitoring period (i.e. at recruitment, expected ≥3 consecutive weeks for ≥2 times during the 9- month monitoring period) Subject currently enrolled in other clinical trials related or involving the study of the respiratory system History of near-fatal asthma Women who are pregnant, nursing or intending to become pregnant during the time of the study Absence of health insurance coverage (applies to French centres only)