Hi MPOU EKOUYA Syntyche AssuResDsiSiiSmi,
Thank you for your question! We understand your need to make page translation easier by setting French as the default language. However, by design, SharePoint Online does not allow changing the default language of a site collection after it has been created.
This is confirmed in Microsoft’s official documentation: Can't change the default language for a site - SharePoint | Microsoft Learn
Here are some alternatives you might consider:
1. Create a New SharePoint Site
Since the default language of a SharePoint site cannot be changed after creation, one effective workaround is to create a new site with French as the default language.
Steps:
- Go to the SharePoint Admin Center.
- Navigate to Site Collections > New.
- When creating the site, choose Language: French.
For move data to the new SharePoint site (collection), we can save site/library as templates and create a new site/library with the templates: Create and use site templates in SharePoint Server versions
2. Enable MUI (Multilingual User Interface)
- Go to your SharePoint site.
- Click the Settings (⚙️ gear icon)> Site Information > View all site settings.
- Under Site Administration, select Language Settings.
- In theAlternate Language(s) section, check French.
- (Optional) Check Overwrite Translations if you want to override default UI text with translated versions.
- Click OKto save.
For detailed guidance, refer to Microsoft’s official documentation: Choose the languages for a SharePoint site user interface
User Language Preference:
After MUI is enabled, users can go to:
- My Account → Language and Region → Select French as their preferred language.
- Once set, the SharePoint site interface will display in French for that user—without changing the site's default language.
We hope this workaround helps meet your needs. Thank you for your understanding, and please feel free to reach out if you need help enabling multilingual features or translating content. If the information above is helpful, kindly mark it as an answer. This will also assist others in the community who may have similar questions complexity.
Warm regards,
Rin-L MSFT | Microsoft Community Support Specialist.