use utf8;
use Encode;
use Devel::Peek;

# Same string as you had.
utf8::upgrade( my $string = "\x{c3}\x{a9}l\x{c3}\x{a8}ve\n" );
{ my $string = $string;  Encode::_utf8_off( $string );  Dump($string); }
{ my $string = $string;  utf8::encode( $string );       Dump($string); }

__END__
Output:
SV = PV(0x1bc7290) at 0x1be3f98
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x1bdd440 "\303\203\302\251l\303\203\302\250ve\n"\0
  CUR = 12
  LEN = 14
SV = PV(0x1bc72b0) at 0x1bf12f0
  REFCNT = 1
  FLAGS = (POK,IsCOW,pPOK)
  PV = 0x1ceb1c0 "\303\203\302\251l\303\203\302\250ve\n"\0
  CUR = 12
  LEN = 17
  COW_REFCNT = 1