In its annual report, SOS Homophobie said it recorded 1,977 calls on its helpline in 2012, a 27 percent increase over the previous year.
The group's head Elisabeth Ronzier said the last few months of 2012 and the start of this year were "intense" with hate speech increasing sharply, especially on the Internet.
She said incidents had doubled in October and November when compared to the previous year and tripled in December.
As there are no corresponding figures released by the interior or justice ministries, the SOS Homophobie statistics are the sole barometer of the level of homophobia in France.
The issue of gay marriage has divided France, which is officially secular but overwhelmingly Catholic, with street protests against the bill drawing hundreds of thousands that often spilled over into violence.
The bill was approved last month but has been challenged before France's Constitutional Council. President Francois Hollande has said he will sign the bill into law once the council rules on the challenge. A decision is expected later this month.