Based on saberaltria's Dolphin Keyboard with color emojis and following cvp's instructions, I made a French-Swiss Keyboard.

First install the Dolphin keyboard core.

Then put the 3 files of the archive below in /usr/share/maliit/plugins/com/jolla/layouts/

Start the Dolphin app and in Keyboard settings, chose Emoji Keyboard. Restart Keyboard service.

In the settings of the Jolla, chose "French +" in Settings - System - Text entry - Keyboards.

Reboot the phone.