diff --git a/htdocs/accountancy/class/bookkeeping.class.php b/htdocs/accountancy/class/bookkeeping.class.php
index 7eddb596e58cf..fc3967f022537 100644
--- a/htdocs/accountancy/class/bookkeeping.class.php
+++ b/htdocs/accountancy/class/bookkeeping.class.php
@@ -1366,7 +1366,7 @@ public function update(User $user, $notrigger = 0, $mode = '')
 
 		$this->debit = (float) price2num($this->debit, 'MT');
 		$this->credit = (float) price2num($this->credit, 'MT');
-		$this->montant = price2num($this->montant, 'MT');
+		$this->montant = (float) price2num($this->montant, 'MT');
 
 		// Check parameters
 		// Put here code to add a control on parameters values