I don't think there are hard and fast rules that apply to everyone. Bonds could potentially be put anywhere. You could argue that Bonds fixed income will not grow as much as equity capital gains, so if you put them in RRSP, you will be taxed less in the end. However because Bond income is taxed at a higher rate than capital gains, there is an argument to put them in TFSA, where all returns are completely tax free. In RRSP it's just taxed deferred.
I personally have my bonds in my RRSP along side US Equity ETFs. Due to mandatory RRIF withdrawals, having bonds in there allows you to option to cash out Bonds or Equities depending on the current market when you retire. If a particular year is a Bear market, you can cash out your Bonds to satisfy the minimum RRIF withdrawal and not have to touch your equities at a loss. In Bull market years, you can do the opposite - ie Cash out Equities instead. Having both Bonds and Equities in your RRSP give you this flexibility. This doesn't apply to TFSA as you are never forced to take money out in a given year.
Finally, because Bonds over the long run will grow less than Equities, I prefer to leave just equities in my TFSA, so it can grow as much as possible completely tax free.
EDIT: There is a case to put Short-Term bonds in your TFSA. This is if you think you will need that money in the short term to fund a vacation, house purchase, emergency fund, etc. In that case having Bonds there will give you the same flexibility outlined above. I personally keep my emergency funds separate in cash within High Interest Savings Accounts.