The J1 is part of the newly open set of buildings for Marseille European of Culture 2013
It contains several workshops and photo exhibitions (free) and a permanent exhibition (free if you are below 26) on the Mediterranean cities that made its history, including Tyr, Venice, Genoa, Istambul etc and Marseille.
It is a very interesting and exciting exhibition worth more than 2 hours a visit. It is also very good for kids too.
Note that everything is written in French, but there are leaflets with translations in multiple languages (at the entrance). In addition, there are many people around each city spot inside the exhibition who can explain everything to you in English.
The J1 also contains a large set of activities for kids (many families come during the week end).
There is a cheapish restaurant proposing Mediterranean specialties (changing every day).
The J1 has great views on the harbor and Marseille’s bay. Go there at sunset.
From there, the J4 with its fantastic Villa Méditerranée and MUCEM museum is just 5 min walk in the Vieux Port direction.
The closest metro station is La Joliette (line 2).
Last word: since it is not possible to AC the building, it will be closed during the hot summer months.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.