flex office: adapting spaces to new ways of working

The target ratio varies according to the external mobility and weekly activity cycle of each population.

• Sales, consulting, audit: 0.7 to 0.8 workstations/person (office presence 2 to 3 days per week).
• Project, marketing, IT functions: 0.85 to 0.95 workstations/person (presence 3 to 4 days).
• Accounting, HR, payroll: 1.0 to 1.1 workstations/person (presence 4 to 5 days, handling physical files).
• Management, legal, sovereign functions: 1.1 to 1.2 workstations/person (semi-assigned desks).

These benchmarks stem from our project practice; they are starting points to refine according to the occupancy diagnosis specific to each organisation. The weighted average we observe stands at around 0.85 workstations per person. Applying a single ratio without job-function segmentation creates marked imbalances between over-densified teams and over-resourced teams, to the detriment of employee satisfaction. Market references place the usable floor area ratio between 8 and 12 m² per workstation in open-plan offices, a range compatible with flex zoning provided shared spaces are integrated. Calibration relies on three measurable inputs: entry/exit badging, meeting-room occupancy, and the booking rate of named workstations over a rolling 60-day period.

For the CFO / Asset Manager: translating the ratio into cash flow. At a weighted ratio of 0.85, on a floor of 200 employees, the space saving reaches 30 workstations, i.e. 240 to 360 m² of usable area. At the average 2023 Paris CBD rent (700 to 850 EUR/m²/year), the avoided rent represents 168,000 to 306,000 EUR/year. The Kytom behavioural audit (3 to 4 weeks, 25,000 to 45,000 EUR depending on scope) pays for itself in less than 4 months on this calculation. Unlike the classic real-estate reading that thinks in fixed m²/workstation, flex office calibrated by job function turns a cost item (fit-out CAPEX) into a lever for asset value creation through the reduction of rent per square metre.

When flex office does not apply. Below 60 employees on the same floor, a ratio below 1 loses its economic value: weekly rotation is too low to absorb peaks, and the cost of the behavioural audit relative to the space gain exceeds the 5-year payback threshold. Likewise, for functions with near-continuous presence (banking back-office, sales administration staff with physical files), forcing a ratio below 1.1 degrades productivity without significantly optimising space. The assigned desk then remains the rational solution.

3-to-4-week behavioural audit: 3 structural mistakes to avoid

The preliminary audit determines the success of the flex office rollout. The gap between declared presence and measured presence is systematically underestimated: badging data regularly reveals a significant discrepancy with HR declarations.

1. Sizing on the declared occupancy peak: relying on declarations without objective measurement leads to under-sizing or over-sizing of spaces. Over-occupancy on Mondays and Thursdays masks under-use on Wednesdays and Fridays. The 3-to-4-week audit captures the full weekly cycle and monthly variations.
2. Neglecting the acoustics of shared spaces: the acoustic requirements applicable to offices set a target ambient noise level of around 45 dB(A) in standard open-plan offices, with enhanced treatment for concentration zones. Ceiling treatment, acoustic partitions and absorbing screens generally represent 8 to 12% of the fit-out budget, depending on the acoustic complexity of the project.
3. Rolling out without change management: 6 months of post-delivery support with manager workshops, a usage charter and corrective adjustments. Across our portfolio, we systematically observe a significantly higher adoption rate in projects benefiting from structured change support, compared with those delivered without a dedicated mechanism.

Our reading differs from the profession’s consensus on audit duration. Most workplace firms offer audits of 1 to 2 weeks, presented as sufficient to capture usage patterns. In practice, audits shorter than 3 weeks underestimate monthly variability (public holidays effect, long weekends, sales cycles) and lead to notable discrepancies in the actual occupancy rate. This imprecision then translates into over-sizing or under-sizing that costs, over the lease term, far more than the 2 additional weeks of audit.

Methodological limitation. The 3-to-4-week audit assumes a stable activity cycle. For organisations undergoing major transformation (merger in progress, transformation plan launched, partial-site relocation), occupancy data are biased and the audit must be postponed or carried out in two passes 6 months apart, which delays delivery accordingly.