Just saw this new requirement by the French government:
As of January 30, the French Ministry of Interior specified that travelers age 18 + one month and over must have received a booster dose within 9 months after their second dose (or single dose of the J&J vaccine) to be considered fully vaccinated for the purposes of entry into France. The French vaccine pass – required to enter many public locations including museums, restaurants, sporting events, and numerous other locations – does require a booster dose within seven (7) months of the final initial dose (so the second shot for two-shot vaccines); beginning February 15, the booster dose will need to be within four (4) months of the final initial dose.
-- Taken from the US Embassy in France COVID-19 Information page at https://fr.usembassy.gov/covid-19-information/
If you are not considered fully vaccinated, you must have a "compelling reason" to enter France, test negative prior to and upon entry and have to quarantine for 10 days. Tourism is not considered a compelling reason.
Paris is looking less likely this year .