A bench comprising Chief Justice A P Shah and Justice S Murlidhar rejected the petition filed by Janata Party President Subramanian Swamy.
The petitioner Swamy, in his petition, had asked the Election Commission to hold an inquiry against Sonia Gandhi.
Swamy on Wednesday said that a proper investigation must be done into the matter and it appears the Central Government is planning to hide the facts related to the case.
"Proper inquiry has not been held in the case. It seems that government is trying to hide something and impression must go to the public that no one is above law," Swamy said.
The court, however said, a proper inquiry has been done by the Election Commission and nothing remains to be further investigated in this case.
"We have to see that there is an element of merit in it. From this material, we find it difficult to agree with you. Even in differing opinion of election commissioners (on the issue) we find no merit in it," the Bench stated.
During her visit to Belgium in November, 2006; Sonia Gandhi was awarded the ''Order of Leopold'', the second highest civilian award of Belgium, and an honorary doctorate degree.