Representation criteria (and, if used, public interest clauses) are intended to reflect as much as possible the situation of a wide range of companies, but cannot take into account their full diversity. As a result, few countries allow exemptions from extensions. In the Netherlands, clearly predefined derogation criteria are even a precondition for prorogation. In addition, companies can apply for an ad hoc exemption from the ministry if they can justify an exemption.27 Hijzen et al. (2019) indicate that 191 applications for ad hoc exemptions were submitted by Dutch companies between 2007 and 2015, but only 58 were accepted. Although there are no formal rules on exceptions in Switzerland, companies with annual turnover of less than 1.2 million francs (about 1.2 million euros) were excluded in 2012 (Visser, 2018). Another way to better reflect the heterogeneity of companies and avoid the “single limit” of extensions would be to promote differentiation within agreements, as is the case in the Dutch metallurgical industry, where two agreements are signed and extended in practice, one for companies with 35 or more employees and the other for companies with less than 35 employees. The French reform of 2017 also linked the extension of a sectoral collective agreement to a differentiation of content between large and small enterprises28. Second, the dominant level of negotiation (. B for example, the level of enterprise, the sector level or the national/intersectoral level) does not cover the actual degree of centralization or decentralization. The latter also depends on the rules of hierarchy between the different levels and the possibility for companies to unravel high-level agreements or to opt out of their own agreement in case of economic difficulties. In particular, systems based on sectoral or national/cross-sector collective bargaining are not necessarily centralized.
They may, if they leave little or no room for manoeuvre, to change the terms of the agreements into lower-level agreements; they can be decentralised, but in an organised way, where enterprise-level agreements play an important role in defining conditions of employment, but are subject to specific conditions set either by law or by the social partners themselves. Unions sometimes negotiate a main contract with an employer or employer organization, and then insist that reorganized employers sign the framework contract rather than negotiate an individual contract.