Hey, imagine a Jutland-like battleship brawl outside Mers El Kebir !
There were the three Bretagne-class and the two Dunkerque battlecruisers, quite a potent force (although the best French battleships were not there - Richelieu was in Dakar, Jean Bart still in the shipyard in France).
Against them: one R-class, one Queen Elizabeth, and the mighty Hood.
I would say that the Bretagne can face the older battleships while Dunkerque and Strasbourg try to handle Hood.
The French are at a disavantage because of smaller guns - more or less 13 inch vs the British 15 inch.
The Bretagne-class had 340 mm guns (more or less 13 inch) but they ten of them (five double turrets, two fore, two aft, and a centerline, the later not very useful - it was removed on one of three in the class, can't remember which) so the broadside weight shouldn't be too far from eight 15'in. Of course there's the issue of elevation - Bretagne-class couldn't shoot far enough. I think that issue had been corrected on the Dunkerques.
A duel between Hood and the Dunkerque twins would be awesome. It would be the battlecruiser swan song.
Problem here is that the Bretagne's were RANCID ships. They'd not been given a modernisation since WW1 save for 1 of the class which gave up her amidships turret for a catapult and hangar. Beyond that they'd not seen many changes, and whilst their gun elevation was thankfully increased they are out ranged. They were slow, their armour scheme was bad and we've no clue about French gunnery.
The D&S are good ships but they have their problems too. The French guns whilst basically two turrets glued together, fired as a single unit. So the guns would either fire as pairs at the same time or all four all at once. This produced some nasty effects on their guns accuracy, as the blast of the guns would throw the shells off slightly. Sure its not much but in naval terms its a LOT. They didn't fix this until post war on their surviving ships where an interrupter system was fitted so the guns would fire like half a second after each other. Also they are in no way shape or form built to take 15 inch rounds, and French AA was very weak. Their 37mm gun was basically not up to standard and other than that they had some 50cal MG equivalents and thats it.
The main problem is getting out of the harbour and breaking contact, if the D&S run then thats GREAT for the Hood. They can't fire backwards, she can fire forwards and her guns can penetrate their armour and she's got good protection against their guns. To fight the Hood the D&S have to get into a turning battle which the Hood will oblige whilst trying to pull them back towards the R and QE. The Bretagne's are simply outclassed by the R and Queen, and sure there's 3 of them, but they are very vulnerable to 15-inch rounds. And then what do you do? You get out great, do you then stick at the speed of the Bretagne's which is at best 20 knots, possibly less. Or do you have the D&S run whilst leaving them behind? The Hood's commanders not going to go MUURR ME UM ENGLANDE KAPTIN!!! (and be the usual window licking retards that british military are so often portrayed on this site as) and try fight two ships at once, especially ones that can hurt him. So he lets them go, the arks aircraft can go after them.
Then he turns and joins the R and QE in slaughtering the Bretagne's. Or do they all stick together and pootle along at 20 knots and then its a general engagement where the RN has the advantage of longer ranged guns and aircraft, as well as cruiser and DD support.