Structural telework: mandatory addendum or simple tolerance?

Post-2020, most Belgian SMEs installed a telework practice without ever formalising the legal framework. That was tolerable in emergency mode. It no longer is. Here's why.

Two regimes, one confusion

Belgian legislation distinguishes occasional telework (law of 5 March 2017) — a few one-off days for personal convenience — from structural telework governed by CCT no. 85, which applies as soon as it becomes regular and habitual.

The threshold "regular and habitual" has no quantified definition in the text, but social case law considers that beyond one day per week over an extended period, you switch to the CCT no. 85 regime. In other words: most post-Covid situations.

What CCT no. 85 requires

Structural telework must be subject to a written document — annex to the contract or addendum — containing at minimum:

Frequency and planned days (or scheduling arrangements). Telework location (home or another defined place). Availability slots and time-tracking arrangements. Equipment provided by the employer and any lump-sum allowance. Reversibility arrangements — essential if you want to be able to reverse the arrangement.

The lump-sum allowance — the point that concerns you fiscally

Since 2022, a lump-sum allowance up to €154.74/month (2026 amount) can be paid exempt from social contributions and tax, provided telework represents at least one day per week and a written document frames the situation.

Without a written addendum, this allowance is reclassified as taxable remuneration and subject to ONSS. Regularisation cost: about 50% of the amount paid (employer + employee contributions + withholding). At €154 monthly and 8 telework employees, that's quickly €7,000/year.

The risk in case of accident

An employee injured during a telework day — is that a workplace accident? Yes — if telework is framed by a written document defining the location and hours. Without a written document, the presumption of workplace accident becomes much more fragile, with risk of refused coverage by the insurer.

Formalisation in practice

A well-drafted CCT no. 85 addendum fits on 2 to 3 pages. It's a standardisable document: we regularly deploy the same template across entire teams, in one information meeting and an electronic signature via a qualified tool.