french 75mm shell cartridge/case

[jwp2007]

my friend picked up what appears to be a 75mm french shell cartrige or case at a car boot,it measures 75mm at the open end and is 350 mm in height.it has been crudely decorated with flowers and the words france 1914 1918.have done some looking up and it has the makers name PUTEAUX with a 3 in brackets(3) underneath,a small c and a large t with a small underlined s near the top of the t and a similar mark which appears to be crossed through with an x.cant find a refrence to the other markings which are 64.L.99.R the dots appear to be small triangles, any help much appreciated,

regards,

john.