$s =~ s/(?<=(?<!\d(?=[.,]\d))\p{P})(?!\s)/ /g;

##</code><code>##

$ perl -wle'use charnames (); for (0..255) { chr($_) =~ /\pP/ and print chr($_)
," ($_): ", charnames::viacode($_) }'
! (33): EXCLAMATION MARK
" (34): QUOTATION MARK
# (35): NUMBER SIGN
% (37): PERCENT SIGN
& (38): AMPERSAND
' (39): APOSTROPHE
( (40): LEFT PARENTHESIS
) (41): RIGHT PARENTHESIS
* (42): ASTERISK
, (44): COMMA
- (45): HYPHEN-MINUS
. (46): FULL STOP
/ (47): SOLIDUS
: (58): COLON
; (59): SEMICOLON
? (63): QUESTION MARK
@ (64): COMMERCIAL AT
[ (91): LEFT SQUARE BRACKET
\ (92): REVERSE SOLIDUS
] (93): RIGHT SQUARE BRACKET
_ (95): LOW LINE
{ (123): LEFT CURLY BRACKET
} (125): RIGHT CURLY BRACKET
¡ (161): INVERTED EXCLAMATION MARK
« (171): LEFT-POINTING DOUBLE ANGLE QUOTATION MARK
· (183): MIDDLE DOT
» (187): RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK
¿ (191): INVERTED QUESTION MARK