ESLint RC rule not working, while rule comment works and other rules do

When I use this comment with the following code, it reformats the code:

/*eslint object-property-newline: "error"*/const obj1 = { foo: 'foo', bar: 'bar', baz: 'baz' };

However, when I add this line to my ESLint RC file instead, it doesn't reformat, while other rules seems to apply.

rules: {'object-property-newline': 'error', 'other rules': 'warn',    // ...}

Does anyone have an idea?