If you found this on an official site like the Open Government Portal, it may be part of a technical dataset or geographic "Rare Plant Diversity" record.
RAR files are containers and can be used to deliver malware if the source is untrusted. Before opening: Download File B5C63449671B.rar
Ecosystem Components - Rare Plant Diversity - Download the French ZIP (PDF, JPG) File through HTTP - Open Government Portal. Open Government (Canada) If you found this on an official site
Ensure it is truly a .rar and not a double extension like .rar.exe , which is a common tactic for hiding executable viruses. How to Open It If the file is safe and you need the contents: Download File B5C63449671B.rar