Laws and perceptions on unionisation of staff obviously differ heavily on a per-country basis.
edit: added last sentence
Can't seem to find anything else.
A Workers' Council is a legally recognized body representing employees of a single employer. It has very limited rights and duties, like being informed in the case of mass layoffs.
A union is a body that represents workers in an entire industry. It can have whatever duties the employees feel like giving it.
This doesn't preclude them from making decisions that favor the company over individual employees' best interests if the law allows it, but I can't think of an example of Google breaking employment law in, for example, Germany.
Note also that although France is often cited it actually has a very low unionisation rate, lower than the US, and e.g. the UK is massively more unionised. Unions are mostly active in the public sector. A specificity is that the right to strike is a constitutional right with quite lax requirements and it is a recurring debate that it is abused by unions. Union activity is also extremely protected so if you get elected as union rep it is virtually impossible to fire you for any reason.