Macossierra10126frenchiso

That appears to be (build 16G29 or similar) – the French language version – distributed as an ISO file.

Upgrading to macOS Sierra 10.12.6 can bring numerous benefits, including improved security, new features, and, for French-speaking users, the ability to use your Mac entirely in French. By following this guide, you can smoothly transition to the updated operating system and enjoy an optimized user experience in your preferred language. macossierra10126frenchiso

If you have downloaded a file labeled macossierra10126frenchiso , you likely want to turn it into a bootable USB. While Apple typically provides .dmg files, an ISO can be "burned" to a flash drive using various tools. For Mac Users: That appears to be (build 16G29 or similar)