Why France and neutrality patrols need bases

Would France remain neutral, and could Germany or Italy protect their trade with neutrality patrols?

France has alliance and imperial reasons to support Britain, while German and Italian patrols would have nowhere suitable to base from inside the war zone.

France risked losing British support in a later European war if it declined to help against Japan. French Indochina was also more directly exposed to Japanese land attack than Malaya or Singapore because Japanese forces could approach across the Chinese border. German and Italian neutrality patrols would need ports, supplies, and access to their operating area. Allied bases such as Singapore or Shanghai would not be available to a patrol intended to protect trade with Japan.