Case T-217/06: Judgment of the General Court of 7 June 2011 — Arkema France and Others v Commission (Competition — Agreements, decisions and concerted practices — Market for methacrylates — Decision finding an infringement of Article 81 EC and Article 53 of the EEA Agreement — Imputability of the unlawful conduct — Obligation to state reasons — Principle of equal treatment — Principle of sound administration — Fines — Gravity of the infringement — Actual impact on the market — Deterrent effect of the fine — Repeat infringement — Ne bis in idem principle — Principle of proportionality — Attenuating circumstances — Actual non-application of the agreements — Attribution of liability for payment within a group of companies — Unlimited jurisdiction)