France, which has seen 88 of its troops killed as part of the NATO coalition backing the Afghan government against Taliban insurgents, signed the 20-year "friendship and cooperation treaty" earlier this year.
"Some senators said that based on Sharia rulings we cannot use the word friendship with infidels, so after voting the word friendship was replaced with relationship," Senator Zahra Sharifi told AFP.
The move, which amounts simply to a recommendation as the senate has the power only to approve or reject the document, not to amend it, apparently embarrassed some senators.
"We argued, we said that France has been a close friend of Afghanistan for a very long time," said Mohammad Alam Ezedyar, who chaired the senate session.
"Some senators disagreed, but the important thing is that the pact was approved, and will be sent to the foreign ministry."
A foreign ministry spokesman, Faramerz Tamana, said that after it received the document from the senate, "we will send the treaty to the government of France, and they will decide whether or not they accept any possible change in the document".
The treaty was signed in January by then French President Nicholas Sarkozy and Afghan President Hamid Karzai and was ratified by the French parliament on July 25.
It was also ratified by the lower house of the Afghan parliament before going to the senate.
Afghanistan has signed partnership agreements with several countries, including the United States, but none of the others had included the word "friendship", said Senator Nesar Ahmad Haress.