Requirements set by the EU employment laws and national rules. The following information aims to give an overview of employment contracts rules, but won't cover all the details of the rules and provisions.

1. When you hire staff you should provide them with their terms of employment in writing

Your staff contracts or equivalent written statements confirming working conditions – such as letters of commitment – must contain at least the following information, or give a reference to the relevant law:

parties to the employment contract (employer and employee)
place of work – if there is no fixed place of work, you should highlight that the employee will work in various locations and say where your business is registered
title, grade, category of work or a job description/brief specification of tasks
start date
expected duration of the job if the contract is temporary
number of days of paid annual holidays
length of notice periods for you and the employee if one of you terminates the contract
initial basic salary, frequency of payment, any other components of remuneration
length of the normal working day or working week (working hours)
rules of any collective agreements governing the employee's conditions of work, if appropriate

For annual holidays, length of notice periods, working time and remuneration, you can simply refer your employees to any relevant national/regional laws and administrative provisions.

2. Changes to staff contracts

As an employer, you must inform your employees in writing of any change to their terms of employment. If the change is due to a change in law or administrative provisions, you do not need to give them a written document modifying the original contract.
If your employees will be required to work for more than one month in a different country, including cases of posting abroad, you must provide them in advance with the following information:

duration of their employment abroad
currency to be used for payment of their salary
allowances they may be eligible for while abroad
conditions regarding their return

3. If you hire more than 50 employees...

If your company employs at least 50 people – including staff employed on fixed-term contracts – in an EU country (or at least 20 if it is a branch of a larger business), you are legally obliged to:

inform your staff about recent and probable developments in company activities and the economic situation of the company
inform and consult staff about the current employment situation and its probable development
inform and consult staff about possible substantial changes in work organisation or in contractual relations

You must also make sure you provide the information in good time so that employee representatives have enough time to prepare for consultation on any related issues.
Employee representatives (and any experts assisting them) may not disclose to staff or third parties any confidential information you share with them.