Baseless. During the Indochina conflict, most battles took place inland, in North Vietnam's central highlands or along the borders with China and Laos. Cao Bang 1950, Na San 1952, and the vast majority of Army operations were hundreds of kilometres from the seashore.
By late 1949, unlike earlier on in the First Indochina War, French naval forces on station off French Indochina had been significantly reduced for a number of reasons, including arguably some very false economies. It was thought that airpower and local colonial forces along with army riverine units would be able to more than make up the difference. This quickly proved to be optimistic (though the
Dinassaut units did see their fair share of successes, especially in the south). The local forces though they fought valiantly suffered from much of the new equipment and manpower that they had been promised never materialising. Airpower couldn't really make up the shortfall, especially during the period in 1949 / 1950 when the French Navy had no carriers to spare for deployment to the theatre, having to rely on land based aircraft and seaplanes to maintain some coverage. This allowed the communist insurgents, at times with direct assistance from PRC naval units (it is unclear if there was any direct involvement of the Soviet Navy in the conflict apart from some disguised freighters and the like used to ship supplies), to grab large chunks of coastal areas including a number of ports and harbours, especially in the north of the country. This in turn allowed them to cut off some French sea supply lines while allowing them to operate a number of their own relatively unmolested. The Việt Minh advances into coastal areas was only (temporarily) halted at the Battle of the Day River. So basically it was a case of much of the coastal regions inadvertently ending up being a 'refused flank', rather than there being any lack of trade for naval forces, including battleships had they been available.
And even during the Vietnam war where many fights took place in coastal areas, pulling an Iowa battleship from mothball for shore bombardment did not spare the Americans an humiliating defeat.
I think we can agree that politicians have no problem losing a war regards of the actual situation on the battlefield.
'bribes may possibly have been involved' : provide evidence or credible source. BTW decommissioned naval ships do not belong anymore to Marine Nationale.
I suggested the possibility because during that period there were concerns about ships being sold off for less than even their scrap value. In some cases the sales had apparently been agreed before they were even removed from the naval register. No formal investigation into this was ever launched though, AFAIK. The Jean Bart herself was sold for a bargain price I believe. Of course it was the then Ministry of Defence that had the say over such sales rather than the navy, apologies for not being clear on that point.
Of course, France was not the only country by far to suffer from problems of this sort at the time, the 1970s were a hotbed of corruption so far as Western countries was concerned (with much of the roots being planted during the '60s), one of the reasons the Soviet Union and its allies were by and large winning the Cold War by the latter part of that decade. Though they had corruption problems of their own and when they got out of control in the 1980s during the Gorbachev era they would ultimately help spell the end of the Eastern Bloc and subsequently the Soviet Union herself.
It was much less an issue of yet another conspiracy theory, this time against battleships in MN, than one of ressources and shifting priorities. As shown in the now-deleted topic on Marine Nationale guided missiles ship projects in the 50s and 60s, the then-CEMM amiral Henri Nomy, at the same time as he was the creator of post-war Aéronavale, building a capability that is still a major naval asset today with Charles de Gaulle carrier, also proposed to keep the two battleships after converting them to missile-ship, either with missile types then being developed in France by DCCAN, ECAN Ruelle and Latécoère, or Terrier, Tartar and Regulus proposed by the Americans in 1957.
Amiral Nomy himself may have wanted to keep the battleships in some form, but that doesn't change the fact that there were powerful interests who wanted them out of the way.
On a separate note, with regards as to Amiral Henri Nomy, was there a proposal for a nuclear powered missile cruiser class bearing his name during the 1980s, do you know?