Thanks for posting. This certainly appears to be a fine cognac judging from the deluxe packaging and of course the well known Remy Martin name.
I am guessing there is some real value here. Cognac keeps indefinitely.
Please read this webpage which I wrote just to help people with bottles such as this.
https://www.antiquebottles-glass.com/selling-full-vintage-antique-liquor-bottles/
Get in touch with one of the brokers listed on that webpage who deal in full bottles of vintage spirits.
Do let us know what you discover!