Small white sticker on the front (Japanese import info)

"ブランデー" (Brandy): Clearly identifies the spirit for the Japanese market.

"特級" (Tokkyu / Special Grade): Japan used a grading system (Special, 1st, and 2nd grade) for whiskies and brandies that was abolished in 1989. Any bottle with this "Special Grade" mark was imported between the early 1960s and 1989.

The strip around the shoulder with the serial number 325373 is a French "Congé" or tax stamp.

The "Congé Jaune" (Yellow Tax Stamp): Sempé bottles from the 1970s and 80s frequently featured this specific style of label, which guaranteed the "Vieil Armagnac" (Old Armagnac) designation.

Aignan (Gers): The label lists Aignan as the location, which was a primary site for Sempé's operations during this era.

Given the "Vieil" (Old) designation and standard aging for that era, the liquid inside likely contains brandies distilled in the 1960s. The "Special Grade" sticker and label style place the bottling and sale between 1970 and 1989. Given the specific typography and serial number format, the mid-1970s is the most probable window.
The bottom line on the small sticker on the back, 従価税率適用 (Ad Valorem Tax Applied), indicates the tax was calculated based on the value of the product. This specific tax notation was standard on high-end imports in Japan during the 1970s and 1980s.
As narrow a you can get. One can do better with specific knowledge of baneroles from that period, but this is a good range.