It is true that the Fourth Republic constitution was not simply a re-creation of the Third Republic's. Nevertheless, compared to the *first* proposal for a new constitution--the Communist-Socialist one for a sovereign unicameral National Assembly, voted down in the May 1946 referendum--one can see how the version ultimately adopted was seen as a retreat to the Third Republic. See Albert Guerard's comments:
"The constitution elaborated by the Assembly under the inspiration of two men of keen intelligence, Andre Philip and Pierre Cot [Cot was a Soviet agent--DT], was a bold departure from the Orleanist compromise of 1875. It reverted to the tradition of the old Radicals, so different from the trimmers and time-servers who had later adopted the name. The Senate was abolished outright. The President became an even more shadowy figure than under the Third Republic. The single and omnipotent Assembly elected and could remove the prime minister. It was a Jacobin constitution and paved the way for the autocracy of a majority party. It was passed by a coalition of the Communists and Socialists over the opposition of the M.R.P/S. General de Gaulle, now a private citizen, pronounced against it. When on May 5, 1946, it was submitted to a referendum, it was rejected by 10,583,724 votes to 9,453,675.
"A new Constitutional Assembly was elected on June 2, 1946. There was no sensational change; but since the M.R.P. was now the largest party, Bidault became president-premier with Gouin, Socialist, and Thorez, Communist, as vice-premiers. The second constitution diverged widely from the first but not, as De Gaulle had expected, in the direction of the American system, with a strong and independent executive. It was purely and simply a rehash of the Constitution of 1875, with a figurehead president, a senate renamed Council of the Republic, elected in a very complicated fashion, and a popular chamber or national assembly. Both constitutions were prefaced with elaborate declarations of rights. Both made provisions for a French Union or Commonwealth to supersede the colonial empire.
"Again De Gaulle expressed his disapproval. On October 13, 1946, 9,120,576 Frenchmen endorsed the new regime, and 7,980,333 rejected it. But there were 25,379,917 registered voters: the nine million "yeas" represented only 36 per cent of the electorate. The constitution was evidently a compromise, unloved even by its sponsors. The M.R.P. in particular hastened to say that it was voted to end a provisional situation fraught with discomfort and dangers, but that it was in need of prompt and drastic amendment. So, with perverted logic, France progressed from the provisional to the precarious. It might have been wiser to do without a permanent constitution for a few years longer, or even, like the France of the Ancient Regime and like England to the present
day, to dispense with a written constitution altogether.
"As a matter of fact, the new instrument did not correct the most obvious evil of the Third Republic, ministerial instability. The dissolution of the Assembly an essential feature in the British system was indeed provided for, as it already was under the Constitution of 1875, but with such restrictions that it was not likely to prove a workable instrument. When on December 2, 1955, Prime Minister Edgar Faure dissolved the National Assembly and called for general elections, it was felt that he was not playing the game; and his sharp defeat at he polls on January 2, 1956, was a rebuke for what the politicians considered as almost a coup d'etat. So, cabinets have been even shorter-lived than before 1939. Queuille and Guy Mollet are considered as veritable Methuselahs among premiers, because they managed to wobble and totter uneasily for a whole year..."
https://archive.org/stream/franceamodernhis006433mbp#page/n475/mode/2up