Micro SDHC 32GB CLASS 4, of Amazon.fr

REFORMAT BY YOUR OWN DEVICE
Insert the card into your phone COMPATIBLE MICRO SDHC 32GB UP.
The card should be recognized immediately. Nevertheless, I suggest you re- "format" still USING YOUR DEVICE MENU.
If you're on Android, go to "Settings", then "SD & phone storage." Press "Format SD card". That's it.

EXPERIMENT
After 8-10 weeks of intensive use of my CD .flac encoded and transferred to my cell phone, I did not notice any slowdown, no hesitation during transfers to the phone, playing on the phone, deletions or file uploads on the map (20 GIGAS USED).
This card thus seems reliable.

PURCHASE
From Amazon.com. For the record, a Class 2 32GB worth 95 Euros it is 1 year.