Old chum in Paris collects apparatus for artistic hobby (7)
I believe the answer is:
origami
'artistic hobby' is the definition.
The definition suggests a singular noun which matches the answer.
'old chum in paris collects apparatus' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'chum in paris' becomes 'ami' ('friend' in French).
'collects' indicates putting letters inside.
'apparatus' becomes 'rig' (I've seen this before).
'o'+'ami'='oami'
'oami' placed around 'rig' is 'ORIGAMI'.
'for' is the link.
Can you help me to learn more?
(Other definitions for origami that I've seen before include "Making of paper shape" , "Delicate operations" , "Japanese craft of paper folding" , "Japanese art of folding paper into decorative shapes" , "Japanese art of folding or tearing paper" .)