Définitions
A substantial cause of an employment contract is a clause of the employment contract which affects an essential element of the employment relationship.
To be classified as substantial, the clause must relate to an element of the employment contract which was regarded by the parties to the contract as essential when it was signed, that is to say an element on which the parties’ decision to contract was based.
Examples
- remuneration;
- function;
- place of work;
- and working time.
Non substantial clauses of an employment contract
Conversely, a clause which relates to a non-decisive element for the parties to the contract, or where the parties provided in the contract or in the collective agreement or in the internal regulations for the possibility of a subsequent change to that element, may be classified as ancillary. A clause is to be regarded as non-substantial if the parties have agreed upon a flexibility clause for an element of the contract. Such flexibility clauses may be envisaged by the employment contract itself, internal regulations, the collective agreement, the statute or usage. According to the case law, the implementation of a flexibility clause is nevertheless subject to the requirement of good faith, in accordance with Article 1134 of the Civil Code and its application must not be abusive.
In the event of litigation between the parties, it will be incumbent on the employment courts to determine whether the clause is substantial or non-substantial.