Well, the website says visa is issued within 10 days of a successful interview:
How long after the interview will the visa be issued?
On the day of your interview, if you are found to be fully documented and eligible to receive a fiancé(e) or immigrant visa, the visa will be issued and posted to you within ten days.
Can I collect my visa in person?
No. Each applicant is required to provide a Chronopost envelope (2 kg) 25x36cm for the delivery of his or her visa by mail. Those resident in Portugal must purchase a Chrono Express European Union (2kg). Envelopes can be purchased at La Poste in Fran
http://france.usembassy.gov/mobile/iv-faqs.html
By the way, that link also has an email address for following up on pending cases (you had indicated on another post that the only way to follow up with the embassy is via snail mail):
Any questions regarding a case that is pending at the Embassy should be sent to
ParisConIV@state.gov