SD card unreadable, MBR partition...

My specs:

My problem:

I bought a Sandisk extreme plus MicroSDHC 32go for my new Raspberry Pi 3 🙂

Then, I installed Raspbian on it with this software (http://www.tweaking4all.com/hardware/raspberry-pi/macosx-apple-pi-baker/).

It was working, but I wanted to erase it to install Berryboot (to multi boot my sd, with others os like kali...).

Anyway, I went to Disk Utility and erase my sd, and then... 😢

My micro sd card became invisible!

I can't modify its content or anything...when I plug it to py computer it says: The disk you insert is not readable by the computer.

In the system report, I could see that:

I tried some commands in terminal to recover the sd ( sudo gpt recover or sudo diskutil repairDisk )... but it failed: error: device contains a MBR.

I just want to erase the content of my sd card and to be able to "see" her and install a new os !!

Please help me 😢 I wait so long for my rapsberry pi 3 and now I'm not able to play with it 😟(and sorry for my english, I'm french).

Félix