Karen I know how you feel. I've lived in 7 foreign countries and have studied, to various levels of proficiency, all the languages. It is not only frustrating but insulting when the native insists on speaking English and has an attitude about your level of their language. As you stated, rarely are they more proficient. Moreover, I have found in over 35 years of engaging non-native English speakers and taking the time and care to understand their attempts at English that most do not offer the same consideration to me when I am speaking their language and make a mistake.
I recently returned to France from Barcelona. I really have not met anyone who speaks English well in Spain. This is true for lawyers, doctors and other professionals you would think would have some knowledge of another language. It is appalling that when I was a crime victim the police had no interpreters...and I was in a town with a huge foreign resident population which swelled to become quasi-British in the summer. At the court house, the "interpreter" was from Algeria
and, though I spoke Catalan ok, I wanted to be clear about the process and to ensure my testimony was accurate. We ended up translating from Catalan to French since her English was basically at the English 101 level. I found it close to impossible to find a lawyer in BCN (non-international/business) who spoke English at a professional level despite their claims on their websites or LinkedIn pages. Imagine the desperation tourists or recent arrivals would have who have little or no knowledge of the language. Every large city in the EU should have a government interpreter service, even if via phone or video. Smaller towns should be able to access such services remotely 24/7.
So your frustration is not limited to just France. It is incredible that in the US, which is criticized by Europeans for being close-minded and without global views, that you can obtain an translator in almost any hospital, police station, etc. NYC offers services in over 100 languages. In the US you can take your driver's license exam in any number of languages (I am not sure that is wise for safety reasons).
In all my experiences with government offices, whether it was in Amsterdam, Vienna, Barcelona or Lyon, no one spoke English. No accommodation ... even in Amsterdam ... was given to me in English. I had to conduct my affairs in the local language. It was odd though, other immigrants had someone from the staff available to assist. This was particularly true in Lyon.
I totally get what you wrote about conducting business over the phone. Even in English...too many call centers are in non-native English locations,..it is trying. When you have to speak to someone in an language in which you are not fluent over the telephone, it is close to a disaster. First, the telephone is not a good device for communication per se. The distortion at times leads to frustration because you don't understand each other. This is why I try to always do everything via email or text message. It is in black and white, you have a "paper trail" and you can take your time to understand what was written and form a reply.
I recently read another post on this site about a member who started some sort of Help Concierge type business with assistance nation-wide. This type of interpreter service you seek, albeit probably for a fee, could be part of his offerings.
The issue of liability of the interpretation may be covered by an insurance or simply a signed waiver. I am not a French lawyer so I can not say. I could see paying a flat fee for a truly bilingual person to accompany a client to a meeting.
Let's see if anyone is serving this market niche. As you say, you don't always need a professional translator but an informal but native or truly professional level interpreter.