Use 'in force' to highlight that rules or laws must be followed, as they are legally binding. The curfew is in force, and violators will be fined.
Pro Tip 2/3
Temporal Phrase
'In force' often precedes or follows time clauses, referring to when a law or rule is active. The new policy is in force from January 1st.
Pro Tip 3/3
Current Relevance
Indicates that a regulation or agreement is currently applicable or needs to be followed now. The historic treaty is still in force and must be upheld.