Parties to the crash investigation will include the French (their pax), representatives of airline, manufacturers of the airframe, engines, etc. and the lead agency will be the Egyptians, as it was on their territory. The CVR and DFDR are legally under the jurisidiction of the lead agency for the life of the investigation after which they revert to the owners of the plane. So, Boeing will be there and will have direct access to the boxes. The actual real investigative donkey work will be done by Bureau Enquetes Accidents, who will also be responsible for the read-outs of the boxes. All the parties to the investigation will get the raw information from the recorders, but what reaches the public domain will be up to the Egyptians.
The alleged engine-change and the Swiss ban on Flash seem the most interesting straws in the wind regarding the causes of this tragedy so far.