Ronaldo's double strike in Sunday's final against Germany gave him the Golden Boot award - and Brazil their fifth World Cup crown.
Fontaine does not believe any player will ever match his own record of 13 goals for France during the 1958 finals.
I think I'll take my record of 13 goals to the grave
But he sees Ronaldo's eight-goal haul as a rightful reward for his resolve in bouncing back from the disappointment of the 1998 final and his subsequent injury nightmare.
"I think it's good for sporting justice that Ronaldo scored twice in the final," said Fontaine.
"After everything he has been through and the suffering he has endured, he deserved to be rewarded for his tenacity."
Ronaldo has now scored 12 World Cup goals to put him level with Pele, one behind Fontaine and two behind Germany's Gerd Muller in the all-time list.
His participation had been far from certain in the months leading up to the finals as he was troubled by persistent injury problems.
But Fontaine believes the Inter Milan striker's limited first-team action last season left him better prepared to star in Japan and South Korea.
"He was fresher than the others because he had not played so much - he only started playing again three or four months ago," Fontaine said on his personal website.
"But it is great news for football that he has won the Golden Boot - it's morally right."
Fontaine added: "My record of 13 goals in the World Cup finals still stands. I think I'll take it to my grave!"