4 sentences

1. 此处严禁烟火。

   cǐ chù yán​jìn yān​huǒ.

   Smoking and open flames are strictly prohibited here.

   Source: Dong Chinese Dictionary

2. 公共场所禁烟。

   gōng​gòng chǎng​suǒ jìn yān.

   Smoking is prohibited in public places.

   Source: Dong Chinese Dictionary

3. 这里是禁烟区，你不能在这里抽烟。

   zhè​lǐ shì jìn​yān​qū, nǐ bù​néng zài zhè​lǐ chōu​yān.

   This is a non-smoking area; you cannot smoke here.

   Source: Dong Chinese Dictionary

4. 他公然在公共场合违反禁烟规定。

   tā gōng​rán zài gōng​gòng chǎng​hé wéi​fǎn jìn yān guī​dìng.

   He openly violated the smoking ban in a public place.

   Source: Dong Chinese Dictionary