After reviewing the actual treaty texts, I eventually have decided that no, France was not in violation of the main naval treaties. This is despite the various blurbs from Wikipedia that I pointed out in the comments. How so? Well, let’s go through the situation and treaties and pull some threads in a linear fashion.
The Washington Naval Treaty (copy at the Library of Congress) was signed in early 1922, with a listed expiration date of 12/31/1936. France was allocated 175,000 tons (177,800 metric tons) in Chapter I, Article IV. Chapter II, Part 1, lists the 10 ships that France could retain (details can be found on Wikipedia), namely:
- Danton class (Condorcet, Diderot, Voltaire), 4x10” guns, 18,800 tons, 19 kts, laid down in 1907/1908 and finished in 1911, generally considered as pre-Dreadnought battleships. These ships were converted to training ships in accordance with Washington Treaty guidance. Condorcet and Voltaire survived to see World War 2. This treatment is similar to several listed ‘retain’ ships for the UK and the USA.
- Courbet class (Courbet, Jean Bart, Paris, France), 6x12” guns, 23,500 tons, 21 kts, laid down in 1910/1911 and finished 1913/1914. Note that the France struck an uncharted rock and was lost in August of 1922.
- Bretagne class (Bretagne, Provence, Lorraine), 10x13” guns, 26,600 tons, 21 kts, laid down in 1912 and finished in early 1916.
- (The Normandie and Lyon classes, which potentially could have become “post-Jutland” ships, were never finished, or even started in the case of the Lyon.)
These 10 ships total some 221,170 tons, in excess of the 175,000 tons allocated. Dropping the roughly 55,000 tons of the aged Danton class brings the total for remaining true battleships under this number. Again, this is in line with how the UK and the USA dealt with several old outdated ships.
Further, France (and Italy) were given a special dispensation to “lay down new tonnage in the years 1927, 1929, and 1931”, presumably to allow both states to end up with 3 “post-Jutland” ships on par with the UK and the USA by the mid-1930s. Under Part 3 (“Replacement”) Section II one finds the proposed schedule for “Replacement and Scrapping of Capital Ships” for France. In addition to the three starts previously mentioned, there are also slots in 1932 and 1933 noted. New ships are slated to be completed 3 years after start, with the retained ships to be scrapped gradually between 1930 and 1936, leaving France with 175,000 tons of new ships in 1936. A note under the table for France further states “France expressly reserves the right of employing the capital ship tonnage allotment as she may consider advisable”, keeping only under the 35,000 ton limit per ship (so in theory they could build more than seven sub-35,000 ton capital ships).
With the Great Depression, France did not start new ships in 1927 or 1929, and it is not clear if they would have intended to start one in 1931 either if nothing had happened. But, several things did happen. First, the Italians started building 4 new heavy cruisers, laying down Zara (11,000 tons, 8x8” guns, 32 kts) in mid-1929. These heavily-protected cruisers with 8x8” guns were strong competition for the old French battleships, and would threaten shipping between the North African possessions and France. Second, the Germans laid down the first of the Deutschland class (6x11” guns, 10,000 tons, 26 kts). These also outclassed the old French battleships and could threaten French shipping in the Atlantic.
These developments led to the Dunkerque class (Dunkerque and Strasbourg) with 8x13” guns, 36,000 tons, and a 29.5 knot speed. The two ships were laid down in 1932/34 and commissioned in 1936/38 respectively. Together they were compliant with the Washington Treaty as the 1927/1929 starts.
However, the Washington Naval Treaty had been extended by the London Naval Treaty which entered into force on 12/31/1930, expiring on 12/31/1936. As stated in Part I, Article 1 the London Treaty states “The High Contracting Parties agree not to exercise their rights to lay down the keels of capital ship replacement tonnage during the years 1931-1936 inclusive as provided in Chapter II, Part 3 of the Treaty for the Limitation of Naval Armament signed between them at Washington on the 6th February, 1922”. In other words, replacement construction was pushed out an additional 6 years, except for the French and Italian 1927/1929 starts. A further point is this ‘holiday’ did not apply in the case of ships accidentally lost or destroyed, which is important. As well, old vessels could be retained until replaced even if they were listed for scrapping in the Washington Treaty.
The Second London Naval Treaty, discussed in early 1936 and going into force in July 1937, had some additional terms. The fact that it was delayed a bit from the end of the (in retrospect first) London Treaty seems mainly to be caused by it being difficult to get agreement given the world scene by then. Capital ships were considered ‘overage’ at 26 years (it had been 20 in the original Washington Treaty, the first London treaty pushed that out by 6 years). The so-called ‘escalator clause’ allowing and increase from 14” to 16” guns would occur if any party failed to sign on by April 1st, 1937. Japan withdrew early on, and Italy never signed. Further, the Second London Naval Treaty also contained a clause in Article 26 allowing for changes “If the requirements of the national security of any High Contracting Party should, in His opinion, be materially affected by an change of circumstances…”, a fairly broad option.
So, how would these treaties apply to the Richelieu and Jean Bart, with the first laid down in October of 1935, and the second in December of 1936? First, because of the loss of the France in 1922, after the signing of the Washington Treaty, the French were short one of their ships, allowing for the replacement clauses in the various treaties to be applied, at least to the Richelieu. Second, with a 26-year capital ship life, the surviving Courbet class ships would nominally age-out in 1939/40. With the 3-year build times in the treaties, laying down new ships in 1936/37 would fit the replacement clauses as well. Finally, between the Italians starting the Littorio battleships in 1934 and the signing of the Anglo-German Naval Agreement in 1935, France could readily retroactively apply the national security clause included in the Second London Naval Treaty.
Bottom line is that France had many valid reasons under the various treaties to start building the Richelieu and Jean Bart when they did.