Background: Increasing drug prices strains budgets. Assessing the relation between added benefit and prices can help clinical decision-making and resource allocation. Methods: We assessed, over a period of 13 years, the relation between added therapeutic benefit and prices for drugs to treat solid tumours in France using the French High Authority of Health Scale (ASMR) and the European Society for Medical Oncology-Magnitude of Clinical Benefit Scale (MCBS). Results: In total, 36 medications were approved for 68 indications. There was a weak correlation between ASMR and MCBS scales (Spearman's |ρ| = 0.28). Drugs had low added benefit on both ASMR (71%) and MCBS (49%). Mean monthly price for new drugs was €4616 (S.D., €3096), ranging from €1795 to €19,675 and increased by 47% comparing 2004-2012 with 2013-2017. The mean monthly price difference of new drugs over their comparator was €3700 (S.D., €3934) ranging between a €13,853 decrease and a €19,675 increase. There was a weak but statistically significant correlation between ASMR and price (|ρ| = 0.35, p = 0.004) and between MCBS and price (|ρ| = 0.33, p = 0.005). Correlations between added benefit and prices were similar or higher for first indications (ASMR, |ρ| = 0.37, p = 0.030; MCBS, |ρ| = 0.48, p = 0.004). In first indications, mean monthly prices increased €3954 for drugs without ASMR added benefit. The mean annual price and price increase for first indications offering no ASMR benefit was €57,312 and €47,448, respectively. Conclusion: Prices and benefit are weakly correlated. However, prices increased substantially even for drugs with no added benefit.