Ok - this is a very pleasant, large, business hotel. It just isn't very interesting and I'm slightly baffled by the rave reviews on Tripadvisor.
The room was comfortable (the bed, exceptionally so). The bathroom was well equipped and spacious. The air conditioning in our room was ineffective and was not repaired, despite a call to reception.
On a hot day, the pool area was desperately overcrowded so as to make it virtually unusable.
We've stayed other Sofitels and visit the one in London from time to time. The Marseille outpost is very similar to the others, except on this occasion the usually slick service was lacking. By way of example, it took a baffling 9 hours and three requests to have our luggage brought from the front door to our room.
The service in the bar was staggeringly incompetent and the bar food menu was poor. (Avoid the sushi - some of the worst I've ever encountered but at eye watering prices).
On a positive note, the concierge was excellent. He was charming and secured us an excellent table at nearby Peron, which was superb.
Overall, I would say this hotel is fine. Big, clean, comfortable, a nice view - but that's about it. I find it difficult to heartily recommend or to envisage rushing back in a hurry.