Tour Guide wanted for our group of 7, 3 children ages 6, 8, 13

Context Travel has several excellent tours which can be given as a private family tour - just enter your travel dates and check "family".
I haven't been on a private tour, but I've been on several of their other tours and can highly recommend this company.
https://www.contexttravel.com/cities/paris

Paris Walks.. they have private tours just for families.

I took a Rick Steves Family tour and the tour used ParisWalks guides ( two of them as we divided into two groups of 13 for the tour of the Louvre).. We had IRIS and if you can get her you will be lucky.

I have been to Louvre many times.. thought this would be old hat for me.. but my 11 yr old daughter had not been so we went along on the tour ( we could have just done our own thing as we often did on the tour) .. and I am so glad we did.. Iris showed me things I had never seen before.. even in exhibits I had been through 1/2 a dozen times already.. she kept all the kids ( aged 8-17 on our tour) interested and motivated to learn.. without boring us adults.

The name is Iris Grossman and she is a treasure..

Our tour was quite a few years ago now.. and many trips since.. and I still remember her name.. and I just checked.. yes.. she still works there !

Even with the most engaging guide on a family oriented tour, it is very likely your 6 and 8 year olds will be bored! I speak from personal experience; we spent 2.5 weeks in Paris this past July with our 7 year old daughter. My advice is to skip the tour for your younger kids, maybe have them visit a park with one of the adults while others are on the tour. You could also make up your own tour. Paris By Mouth lists all the chocolate shops on their tours on their website. We enjoyed this with our daughter much more than the expensive organized tours. Enjoy Paris!