Google has a strict policy on the kinds of content that can be left in a Google Review.
Here is a list of content not allowed in Google Reviews and on Google Maps.
Spam and Fake Content
In the world of Google Maps, spam and fake reviews are quite common to find. Some ways to tell if a review is spam or fake is by checking the profile a review came from. You can see the history of reviews left on the profile. If someone left 30 reviews for 30 different law firms, they are either extremely unlucky or fake.
Reviews should be about a personal experience involving the specific location. Reviews should not turn into a forum or a personal rant.
The content in reviews must uphold the laws in the area. Links to landing pages pointing to restricted goods, email addresses, or phone numbers to purchase illegal products and promotional offers for restricted products are against Google policies. Images of menus and images where alcoholic beverages are present but are not the main focus are fine.
Any images that infringe on anyone's legal rights, including copyright, sexual abuse imagery, dangerous or illegal acts, illegal products and services, graphic images or content backed by terrorists are against Google policies
Terrorist organizations are not permitted to use Google review service for any reason, including recruitment. If posting content related to terrorism for an educational purpose documentary, scientific or artistic purpose, be sure that the audience understands the context.
Sexually Explicit Content
All sexually explicit material is not allowed. Any content relating to children will be removed but reported to the National Center for Missing & Exploited Children and law enforcement.
Any content containing obscene, profane, or foul language will be removed.
Dangerous & Derogatory Content
Threats or advocates for harm to themself or others will be removed. Harassments, intimidation, or bullying will be removed. Any review that incites hatred promotes discrimination of an individual or group for ay reason will also be removed.
Individuals on Google Maps are not allowed to mislead or deceive others with false representations. Do not claim to represent anyone or any company unless you were given the authorization to do so.
Conflict of Interest
Do not review your own business. Do not leave reviews about current or former employees. Do not post content about a competitor to manipulate their ratings.