title_body: Tea vs. coffee paper filters: are they interchangeable?
upvoted_answer: They will function ok for your intended use. Some fines may get through and produce a bit of sludge in your cup.
  Your bigger problem is that you won't be able to fit enough coffee into a standard size teabag to get good dosing. French press dosing is between 1:10 and 1:16 coffee to water ratio, which is 16-25g per 235mL or freedom 8oz cup. For the same size cup, you only need about 2g of tea. Teabags are sized for the latter. You may have to use up to ten per cuppa to fit the desired amount of coffee.