Potentially in a sort of de facto sense, yes, between 1722 - 1789 Versailles may have operated similarly to a capital of France, but I would hesitate to apply that particular terminology. In an absolute monarchy such as Bourbon France was the apparatus of government operated so firmly around the person of the monarch that wheresoever the monarch found themselves permanently residing had pretty good claims to capital status.

However, one thing that is important to remember with Versailles is that the residence of the King there did not necessarily detract from the pre-eminence and importance of Paris. Throughout the 18th century Paris was by far the largest city in France in terms of population, and the relative proximity of Versailles to Paris meant that many of the 'luxury' industries that sustained the Versailles nobility also contributed to the Parisian economy (an effect that was actually keenly felt during the Revolution). Furthermore, many of the less wealthy nobles who kept a sort of year-round presence at Versailles rented or owned townhouses or rooms of some sort in Paris itself.