British Forces

BC Hood  Force H   Vice-Adm. Sir James Sommerville—Flag
BB Resolution Force H
BB Valiant  Force H
CV Ark Royal Force H    Capt. C. S. Holland
CL Arethusa  Force H
CL  Enterprise Force H
DD  Faulknor Force H
DD Foxhound Force H
DD Fearless  Force H
DD Forester  Force H
DD  Foresight Force H
DD Escort  Force H
DD Keppel  Force H
DD Active  Force H
DD  Wrestler  Force H
DD Vidette  Force H
DD Vortigern Force H

The following information is thought to be Ark Royal’s aircraft complement at the time of the Mers-el-Kebir operation based upon source #4.
800 Squadron  12 Skuas
803 Squadron  12 Skuas
810 Squadron  12 Swordfish
818 Squadron    9 Swordfish
820 Squadron    9 Swordfish

French Forces
   Admiral Marcel-Bruno Gensoul

BC Strasbourg    Captain Barrois
BC Dunkerque    Captain Louis Collinet

2nd Battleship Division
   Rear- Admiral Bouxin – Div. Commander
BB Provence  Captain Gabriel Barois
BB Bretagne* Captain Le Pivain

SD Mogador
SD Volta
SD Tigre
SD Lynx
SD Kersaint
SD  Le Terrible
Seaplane Tender Commandant Teste  Captain Lemaire

Also known to be located in the Port of Oran (just to the east of Mers-el-Kebir) the French had the following:

(10) light DD’s (600-tonners)
(6)  submarines (only 3 were operational)
(13) smaller warships

French Shore Batteries in the Area:
1. Fort Santoni – 3x194mm guns
2. Gambetta Battery – 4x120mm guns
3. Espagnole Battery – 2x75mm guns
4. Canastel Battery – 3x240mm guns

*Sunk

Sources:
1. Chronology of the War at Sea 1939-1945 by J. Rohwer & G. Hummelchen
2. The French Navy in WWII by P. Auphan & J. Mordal
3. The Naval War in the Mediterranean 1940-1943 by J. Greene & A. Massignani
4. Carrier Operations in WWII Vol. 1: The Royal Navy by D. Brown