If the creditor wants to recover a debt by distraint, he cannot do it by means of an invoice or a signed contract only, but he needs a title of execution.
The title of execution is an enforceable document to which the law recognizes an enforceable quality that makes the claim official. Typically, the enforcement title can be a judgment or an injunction.

The injunction (Decreto ingiuntivo) consists of an order of payment issued by the Court, after demonstrating the existence of a claim against the debtor. Specifically, the creditor shall identify a certain exact amount of money (or goods) and provide written proof that his claim is fully grounded (e.g. contract, invoice etc.).

Once the injunction is issued,  the creditor shall notify it, within 60 days and the debtor  thin 40 days the debtor may:

1. Pay, avoiding foreclosure proceedings and distraint;
2. Oppose to the injunction, thus starting a trial;
3. Not pay: the injunction becomes final and the distraint may start.

If the debtor does not pay, the creditor notifies the writ of enforcement, which obliges the debtor to pay within 10 days, otherwise this represents a title to seize his assets.        
If the debtor did not pay within this deadline, enforcement shall proceed by choosing the type of distraint: 

1. Distraint of movable property (e.g. cars, jewels etc.);
2. Distraint of immovable property;
3. Distraint from third parties: it concerns credits or goods of the debtor which are in possession of third parties.

The creditor may select the assets to be distrained. However, if he selects more assets or an asset of higher value than the debt, the debtor may apply to have the selection restricted.
The distraint becomes ineffective if the assignment of the goods to the creditor has not been collected by him, within 45 days.