old chairs

the 2 chairs have been in my family ever since i can remember. 1 was re-covered about 40 yrs ago. the other has never been re-covered, it still has the original material on it. neither of them has had the wood re-done but, the wood is in great shape. nothing is broken, cliped, scratched etc... they are still usable. i clear the wood every couple months and nobody sits in the chairs.
what my dad has told me is his great aunt pae brought the chairs from france when she migrated to the usa in the early 1900's. i'm told they are about 150 yrs old, victorian era. i have both chairs now and i'm wanting to know what the value of them is. i do not have pictures or know who made them. but if i could have somebody tell me what to look for and what kind of pictures they need to be able to tell us the real value of these chair. that would be great.