What would be the longest possible duration for tourist visa(not 30 day stamp)a French National could obtain including extensions and in/outs? Doesn’t matter where they apply, in France or embassy in another country is fine.
TLDR : Answer Summary
The longest possible duration for a tourist visa for a French National includes various options. A single-entry tourist visa (SETV) allows for an initial stay of 60 days, which can be extended for an additional 30 days, and potentially a final extension of 7 days—totaling 97 days, followed by the necessity to leave the country. Multiple border runs can extend stays with visa-exempt entries, but this can be limited to twice per year. Alternatively, the Multiple Entry Tourist Visa (METV) can be obtained, permitting multiple entries for 6 months, with the requirement to do a border run every 60 days. Some mention the "Elite" visa as a long-term solution, offering up to 5 years, though it is expensive. The application can be done in France or at a Thai embassy in another country.