Thanks Kevin ! In the pdf file (Chapter 6) you sent me Don Bradford gives an account of Operation Premium (he commanded MTB 682 during this operation).
Source combinedops.com :
Sunday, February 27, 1944
A raid on the Dutch coast near Wassenaar on 27/28 February 1944 by a small group of Commandos from No. 10 Inter Allied Commando who had embarked at Great Yarmouth on MTB 682.
Captain Charles Trepel and the 5 other French Commandos who left the MTB that night were never heard of again until the area around Scheveningen was liberated. During investigations into their disappearance their graves were found, five described as unknown Allied airmen, and one as unknown English soldier. The graves were disinterred and the men identified. There have been numerous suggestions as to how they met their death from drowning to execution."
This Dutch site provides more info about the fate of the French commandos who took part in this operation :
http://katwijkinoorlog.nl/commando-raid ... aarseslag/