For Citroen C5 years 2004 - 2008:
If the car dashboard is identical to the one below:

You need to buy a suitable 1 din dashboard kit, this is the dashboard kit that I recommend: https://www.ebay.com/itm/CARAV-11-016-1 ... Sw2jNbxMl8
Then you can install Joyforwa single din 7'',8'' and 9'' android autoradio: https://www.joyforwa.fr/android-8-1-0-a ... e-din.html
For Citroen C5 2008+:
If your car dashboard is the same as below:

You may need to do some modification of your dashboard to install the Android 1 din car stereo. We have the special Canbus decoder that supports the original car steering wheel control. Below are the customers review pictures for your reference:
Car radio 7 inches 1 din installed on Citroen C5:

Car stereo 8 inch 1 din installed on Citroen C5:

Car radio 1 din 8.8 inches installed on Citroen C5:

For Citroen C4 Picasso 2007-2013:
If the dashboard of your car is identical to the image below:

You can install our 7 '', 8 ''and 9' '1 din car radios . You must also buy the special Citroen Canbus harness
This is the 8 "single din unit installed on the Citroen C4 Grand Picasso 2008:

For Citroen C1 2005 - 2014:
If the dashboard of your car is identical to the one below:

You can install the single din and double din car radios.
You will find below the 6.2 inch 1din car radio installed on the Citroen C1:

If you want to install the double din car stereo, you need to buy a suitable double din dash kit, the size should be 178 * 102mm.
You can install our car radio 7 '' double din. Below is the review picture for your reference:

If you have any other installation suggestion, please post here, we can discuss together.