To remove your "… with Netatmo" connected installation from your Google Assistant, you have to remove the "Home + Control" service. Take the following steps:
1- Launch your "Google Assistant" application and select the blue button at the top right-hand corner of the page.
2- Go to settings and select "Home Control" in the list of services.
3- Select "Manage accounts" from the menu at the top right-hand corner of the page.
4- Select the associated "Home + Control" services and select "unlink account".
5- Confirm by selecting "Unlink" one more time.
Your "… with Netatmo" connected installation can no longer be accessed by your Google Assistant.