In Finland there are fixed-term and permanent contracts. Fixed-term ones are extremely hard to terminate one sidely for both parties (excluding separate terms in the contract like probation period). Permanent contracts require certain amount of notice by default. Employees notice period is 14 days if contract has lasted less than 5 years, 1 month otherwise. Employer's notice period are: 14 days if contract has lasted less than a year, 1 month for 1-4 years, 2 months for 4-8 years, 4 months for 8-12 years and 6 months for over 12 years.

Contract and CBA can affect these. The only restrictions law has is that employee's notice period cannot be longer than employer's and that the maximum is 6 months, but CBA can set minimums. The CBAs that I have read set those law's default notice periods as the minimum. Vast majority (I believe about 80-85%) of employees in Finland are covered by some CBA.