I am always suspicious about waterproof jackets that do not quote the breathability in numbers I've seen before. The jacket has an OK but not outstanding waterproof resistance at 15,000 mm of water (ie the fabric will support a water column 15m high without leaking). But it does not quote the standard measure of breathability which is how much water vapour in grams will pass through one square meter of fabric in 24 hours. This is known as the Moisture Vapour Transmission Rate (MVTR). An MVTR of 20,000 gm/m2/24hr is good for active use, 30,000 or more is good for highly aerobic use. For comparison, some of the Endura MT500 fabrics have an MVTR of 60,000! But of course they are much ore expensive than this Decathlon jacket.
Goretex use a different method known as Resistance to Evaporative Heat Loss (or RET), which is what Decathlon appear to be using. In this method the lower the number, the more breathable a fabric is. Six will give you a good level of breathability for more active use. While four or less will give you the best level of breathability for highly aerobic use. It looks like a good jacket for walking in the rain.