In practice it happens very often that an employee of a company - after the period of employment - using data and information of previous employer (such as the list of customers and suppliers) to provide them with an competitor or to start their own business. This is very dangerous behavior because the data in question are, for the holder, an important resource and have a significant economic value.
Many believed that these behaviors are now punishable under Article. 98 D. Decree no. 30/2005 (Code of Industrial Property) specifically provides that
Article 98.
Object of protection
1. Are the subject of protecting corporate information and technical and industrial experience, including commercial, subject to the legitimate control of the holder, if such information:
a) is secret in the sense that they are not together or in the precise configuration and assembly of its components, generally known or easily accessible to experts and professionals;
b) have economic value because it is secret;
c) be submitted by the person lawfully in control of the subject, to be considered reasonably adequate measures to keep it secret.
Of opposite sign is the orientation of the Supreme Court that, with the ' Ordinance No. 16744/2008 , has ruled on the case of removal of some of the archive file containing customer information unlawfully stolen by a former employee and made available to competitors. The Supreme Court has indeed held that such conduct is not per se unlawful because the information in question, though confidential, secret should not be considered as
news, who take stolen and then used improperly, are known or easily accessible to experts and practitioners, and much reason to have no economic value.
This statement, referring to the list of customers and their addresses (postal and electronic) does not convince me. It is my opinion that it is not knowledge "generally known or readily accessible to experts and other stakeholders", firstly the fact that these data be stolen and given to competitors speaks volumes about the competitive advantage they represent. In fact, if the mailing address of the client (or partner) is as easily acquired, the same can not be said for the e-mail address and phone number of decision makers of the company. This information, in fact, are not easily accessible so that a portion of their value is represented by its own temporal advantage that the competitor acquires when it becomes available, in addition to this, the 'former employee may provide other elements (such as income, financial circumstances, buying habits, etc..) can "enrich" the mere list of customers.
Instead, following the policy of the Supreme Court the removal, disclosure to third parties and use such lists would be unlawful only when it constitutes unfair competition (in this case will not be a sufficient number of episodes being necessary 'activities aimed at sustainable transfer of customers as established the Supreme Court with another ruling that found here ). So to those who, worried, asked me how they can protect themselves from such behavior, I suggest to include specific clauses in employment contracts and agreements of cooperation, perhaps with a provision for penalties in order to bind all the need to do out this information from the company.
Because, as said Miguel De Cervantes , is "twice a fool who, revealing a secret to another, asked him earnestly not to mention it to anyone." 
[...] Mr. Simonetti Nazarene: [...]
[...] Spataro, thank you, I was interviewed on civile.it on the recent order no. 16744/2008 of the Court of Cassation on removal and reuse customer information from the archive [...]