Hello

After completing an a1 a2 b1 b2 level of french you can apply for translator posts in mncs like HCL,TCS, WIPRO etc( for this you will have toclear the TFC or TAF exam),  write articles and posts for travel & tourism magazines and websites and much more but since you have mentioned the age factor (which probably might be a hindering factor) you can always work at education institutions. You can even start your own youtube channel to teach french if you want.

Another great option for you is translator, proofreader, interpreter, editor, content writer,  howevr for these you have to get an almost native level of proficiency over the language.