Clio diesel DPF failure

Sounds like a blocked DPF. Reduced power and smoke are classic symptoms. What sort of driving do you mainly do? Short trips can clog them up. Have you noticed any changes in your fuel efficiency? Has the engine management light illuminated? You could also have a faulty sensor giving bad readings, exacerbating the issue by forcing extra regeneration cycles.

Thanks for the info. I mostly do short journeys around town. Fuel efficiency has decreased noticeably. The engine light did come on a few weeks ago, then disappeared. Could a diagnostic tool read out relevant error codes in order to pinpoint the sensor in question?

Okay, short journeys are killer for DPFs. The light coming on and off suggests the ECU has been trying to resolve the issue with regeneration, without success. A diagnostic tool should indeed pull relevant error codes. However, given the symptoms and mileage, I'd put money on the DPF itself being defective, probably beyond cleaning. You're likely looking at replacement; best get it checked at a reputable workshop that deals with exhaust systems.

Thanks for your help! I took it to a workshop, and they confirmed the DPF was indeed defective. The replacement, including labor, came to 1550€. Appreciate the advice!