No it will not, the 2.9 and 3.0L are 2 totally different motors.
It is important to know the oil capacity of a given transmission. For a C4 Transmission its oil capacity is 9 US quarts.
The Ford C4 transmission can be identified by the following.The pan will be square and have 11 bolts.If there are 17 bolts, it's a C6.
C4 transmission
A c-4 transmission has 3 gears.
It usually goes in where the dipstick for the transmission is.
There are many ways to learn about the transmission on a Citroen C4 Picasso. One could take a course for engines and transmissions. Also one could purchase a workshop manual for a Citroen C4 Picasso.
c4-AOD
c4 auto
type f transmission fluid only
Type F Automatic Transmission Fluid
The Ford C4 transmission will fit.