Article 18 — Limitation period for the enforcement of fines and periodic penalty payments

1. The power of the Commission to enforce decisions taken pursuant to Article 15 or 16 shall be subject to a limitation period of five years. 2. The limitation period referred to in paragraph 1 shall begin to run on the day on which the decision becomes final. 3. The limitation period for the enforcement of fines and periodic penalty payments shall be interrupted: (a) by notification of a decision modifying the original amount of the fine or periodic penalty payment or refusing an application for the modification of that amount; (b) by any action of the Commission, or of a Member State, acting at the request of the Commission, intended to enforce payment of the fine or periodic penalty payment. Each interruption shall start time running afresh. 4. The limitation period for the enforcement of fines and periodic penalty payments shall be suspended for so long as: (a) time to pay is allowed; (b) the enforcement of the payment is suspended pursuant to a decision of the Court or pursuant to a decision of a national court.